As always, a lot depends on your uses and workflow, which you don't say much about, so you'll just need to evaluate that based on the rest of the discussion.
Sitting on my desk right now are an M1 Pro 16" 16/1T hooked up to 27" 5K and 32" 4K external monitors, and an M2 MacBook air 8/256.
To your points in order:
1) the year difference between the M1/M2 MBP's isn't going to be a big deal, they're running on the same underlying hardware. Apple *could* end updates for the M1 version a year or two earlier, but it's somewhat more common to keep similar hardware platforms up to date together, and then end support for them together. Regardless, the M1 macs are a HUGE installed base, and Apple has a lot of incentive to keep them updated for a long time - it's going to be a really big deal the day they declare M1's no longer supported by MacOS.
2) Generally speaking, I'd expect a 32GB M1 Max to keep performing at a high level longer than a 16GB M2 Pro. The extra RAM and GPU should allow a considerably longer performance runway over the M2's relatively modest optimizations. The M2 is a solid upgrade over M1, and all things equal, you'd pick an M2 family over M1. However, M1 Max with twice the RAM should trounce the M2 pro at almost everything. There may be a couple things where the M2's task-specific hardware is enough to make a difference, but it's hard to speak to that without knowing more about your specific tasks.
3) 14 vs. 16. There's no doubt the 16" MBP is a chonky boi, but the actual differences between the 14 and 16 are modest. I've for many years said that small laptops are amazing when you're carrying them in your bag closed, but big laptops are almost always better when you've opened them for use. The larger screen is usually a much bigger productivity improver than the hardware inside. So, the question is how much you're carrying it around in your bag, vs using it open on a table. An in-between case is on your lap, where the smaller laptop is usually better even when open. I love my 13" M2 MacBook Air, it's fantastic for my walk to campus, then checking email and running powerpoint to a projector for lectures. I'm carrying it around on my back for a few miles a day, and then opening it for simple uses. But I'll still bring the 16" MBP if I'm really planning on doing substantial work like creating a new powerpoint, or editing video, or showing someone a presentation on the laptop where the screen quality and speakers make a big difference. Only you know what the balance of screen size vs carry weight/bulk is for your needs, but I'd generally submit that people over-emphasize the convenience of a small laptop versus the gains of a larger screen when actually using it.
4) 'does any of this matter if I don't end up making use of the extra RAM/CPU' - This is the big question. Did you buy an MBP because you really NEED the extra power? or just because it's cool? I've absolutely bought machines I don't need because the extra horsepower seemed cool, or I was afraid of needing more power late in the computer's life - I'm not giving you a hard time here. I will say that the M1/M2 series in general has enough power that even the base versions can do everything most people need without breaking a sweat. My 8GB M2 MBA edits even 4K video clean and fast, and renders it fast enough I don't worry about it much. There are absolutely people who need the extra GPU power of a Max setup, or the Ultra in the Mac Studio - if you're editing 4K+ video all day, running 3D renders, CAD modeling, etc, there's just bottomless need for CPU/GPU cycles. I'm an avid photographer and fly camera drones for fun. A couple years ago, I really needed a desktop or MBP-level machine to have a chance at handling HD or 4K edit/render efficiently. I've run Final Cut X on a 12" MacBook to edit HD footage, and it was miserable. Today, the M2 MBA handles that beautifully, the M1 Pro MBP is a little quicker, but not enough to bother transferring footage there unless I want the bigger screens.
Long story short, I'd suggest taking a real solid look at how much horsepower you really need, and maybe thinking about whether you should return the MBP and wait a few weeks to grab a 15" MacBook Air when (hopefully) that's announced/available. I'm hoping that'll be a powerful answer to the 'big screen/enough power' question you've posed. I'd love to trade in my MBA and MBP for a 15" MBA... but we'll see how the final product looks.
Thanks a lot for all of this. Extremely helpful.
My current workflow is honestly pretty minimal. I wouldn't say I bought it because it was cool... basically i had my sights set on a MBPro for years and my hope/aspiration is to get back into some video and photo editing. I didn't plan to get the most souped-up option available, as I knew it was beyond my needs, but I was afraid an Air might not be heavy-duty enough if I get into 4k video, and I selfishly wanted the better xdr promotion display and was willing to pay more just for that.
I had committed to $1900 for the base model m2 pro 14", and then immediately after that, I saw this 16" m1 max go on a flash sale for $2499 and people in the comments on Slickdeals were raving about what a killer deal it was... so I figured maybe for just a little more money, it would be a more worthwhile long-term investment. I would never have paid the full $3500 price tag for it, but now that I do have it, I have to admit it's hard to go back to the 14" lol.
So to answer your question, it's definitely above my current needs, but at the same time I feel like I got such a great deal on it, that paying $1800 for the m2 base model with 16gb ram (as it's now dropped in price from $1900) and a smaller screen almost seems stupid, as I got a killer top of the line device with double the ram and storage, plus a larger screen, for only a few hundred dollars more.
that said, my initial goal for getting this was to have something more mobile and easy-to-use around the home. i also want to get back into writing (i know i don't need a macbook pro for that, but in addition to the video editing, that's something i plan to reconnect with as a past hobby), and i thought the 14" was a perfect size for on the sofa, in bed, in a coffee shop, etc., and my concern with the 16" is that it's so cumbersome that i'll never want to use it on-the-go the same way i might the 14".
but at the same time, i rarely leave my house with it, so if i can adjust to using it on my lap then i guess that's a non-issue. i do have a 32" external monitor i can dock it - i'm not sure if that is a vote for, or against, the 16" macbook... my friend was telling me he would just keep the 14" because any time i want a larger screen i have the monitor to connect to, but the 16" screen is definitely quite gorgeous when i'm away from my monitor, and it is so enjoyable to work directly off of, whereas with the 14" it does feel more cramped and i do feel like i'm making more of a compromise when it isn't connected to the monitor, if that makes sense? i wouldn't say i look forward to working off the screen of the 14", whereas every time i open the 16" i'm wowed by how gorgeous it is.
but the flipside of that is that i genuinely prefer the form factor of the 14" in terms of how it feels on my lap, how easy it is to carry around, and just being able to sort of nonchalantly/casually move it from my sofa to the coffee table or pick it up and toss it (not literally) on the sofa next to me, whereas every movement i make with the 16" feels far more fragile and decisive. i really need to use both hands to pick it up and place it down, and it takes up far more space on coffee table, kitchen counters, etc. "Cumbersome" is the best word I can use to describe it. Even just moving back the lid, i feel like i have to be more careful that it won't hit against anything or that there's enough space to push it back, whereas the 14" fits in smaller spaces and i don't feel as worried about damaging it as i do when i'm handling the 16".
i even got a cool little docking stand for the 14" which fit perfectly on my bedside table so that i could carefully stand it upright after use and avoid it falling off my nightstand or the cat jumping up on it, but the 16" is too large and looks goofy when i do this. so those are little quibbles but in day-to-day use i'm concerned they will compound and cause me to have more friction with picking up the macbook -- i'm worried it'll just become permanently affixed to my desk, which sorta defeats the whole point of why i got it in the first place.
but that screen... so gorgeous...
hopefully that might add a little more context or background to where i'm at and what my needs are, if it helps at all, but your previous post was definitely very useful and i appreciate you taking the time to write that all out and address all my concerns/questions.