I'm no Apple apologist, but realistically the market has changed. The PowerMac was a quality desktop computer, and it was priced that way for along time. When we were buying G3 and G4 PowerMacs they were $1600 (about $2500 in today's money) and your only other option was iMac or eMac. When they made the switch to Intel, Apple quit marketing the Mac Pro as desktop, but as a high end workstation. Thats when prices started to get a little crazy and the entry level machine basically went up $1000. Obviously the gap between the 2013 Pro and iMac Pro was far too long, but realistically the CPU technology basically plateaued during that period. Shame on Apple for not discounting the machine, but the 6,1 was still a solid workstation in 2016. I think it's a computer that makes more sense today than it did in 2013 because fast external expansion is more acceptable today. Had Apple offered speed bumps of the 2013 to give it newer GPUs and CPUs I think it would have aged even better. Mac Studio is basically the exact same machine minus the upgradability. You can't possibly consider Mac Pro 2019 and 2023 to be the same class of machine your old PowerMac and Mac Pro were. It probably shouldn't have kept that name. They just aren't in the same league anymore. Apple knows this and has offered Mac Studio for that reason. If a 10 year old Mac Pro can carry your workload, you don't need a Mac Pro, you need a Mini or Studio. Same price point as what you'd have paid for a 2006 Mac Pro and offers pretty handsome specs for the money. Fact is, we have more Mac desktop options now than in 2004 which is absolutely wild to think about.
I wholeheartedly agree that inability to expand/replace RAM and SSD is awful. The way Apple has locked down those "consumable" components in high end desktops is borderline criminal, but they don't want you keeping your Mac around for 12 years. Why would they? They make nothing of old machines. They don't sell the OS anymore, so they want you to spend money on iCloud and a new machine every few years. It's a major bummer for us old guys who love pushing things to the limit and really feeling good about making that initial investment, but times have changed. Nobody is going to push Apple back to socketed CPUs ever again. Maybe there is some hope of socketed GPUs again, but if Apple could at least give users replaceable storage down the road, I'd consider that a win.
For someone who's opening line is "I'm no Apple apologist', you're sounding a lot like one.
The market didn't change, Apple did.
There was then (and there still is now) a plethora of tower PCs available, but the only tower Mac was the Mac Pro.
Apple abandoned that form factor and in so doing abandoned everyone who used the tower (which was mostly pro and power users) and that's why the 2013 Mac Pro bombed. Users couldn't port their storage, couldn't port graphics cards or their PCIe cards - so it was totally unsuitable for most prior Mac Pro users.
Your assertion that Apple don't want you to keep your Mac for 12 years is based on a false premise.
I didn't keep my Mac Pro 4,1 for 12 years because I wanted to, I kept it because I had to. There wasn't another tower Mac I could upgrade to.
All the prior model of Mac Pro's (and the Power Macs that proceeded them), were ALL expandable, yet I purchased every one. Apple received far more money from me at that time than they ever have since, so it's a complete red herring to suggest that upgradability harms sales by prolonging life...it does not.
In 2017, 4 years after the 2013 fiasco, Apple publicly apologise and promise a new expandable Mac which they bring out two years later in 2019.
Which brings us to the next kick in the nuts...price.
I'll use US dollars to keep it simple...
In 2006 when Apple introduced the Mac Pro, it started from $2499.
Six years later in 2012 it started from...$2499.
So amazingly there was no price increase in 6 years and when adjusted for inflation the Mac Pro actually got cheaper in price!
In 2013 when Apple produced the totally unfit for purpose Trashcan Mac Pro it started at $2999 - a $500 increase, but it was still only $100 more in real terms in 2013 than the 2006 model was at $2499 when adjusted for inflation .
So in 7 years the Mac Pro had a real terms increase in price of just $100. In fact, as the 6,1 wasn't discontinued until 2019, you could argue the Mac Pro from 2006 - 2019 had a real terms decrease.
In 2019 That all changed. The 2019 Mac Pro (the first Apple tower since 5,1) and the replacement for the 6,1 started at a whopping $5999 - that's double the price of the model it replaced. Even allowing for inflation that still $2000 more than the 2013 model which would be circa $4000.
It also shipped with a pitiful 256GB storage (that's less storage than the base Mac Pro from 2008) I have more than that on my phone.
in 2023 it got even worse and Apple (again) increase the price to a whopping $7000!
So to reiterate...
When adjusted for inflation the last Mac Tower (5,1) in 2012 cost $2499 (approx $3800 in today's money). It offered user upgradable RAM, user upgradable internal storage and crucially PCIe for everything else (including graphics cards).
By 2023 the Mac Pro offers no upgradable RAM, non upgradable internal storage and non upgradable graphics and is priced at $7000. So all Apple have really done is offered another unsuitable option, they've just amended the reason for the unsuitability.
The Mac Mini, Studio, iMac are all unsuitable as none offer PCIe - something still very important for many in audio (one of the primary reasons we used a tower to begin with), so your assertion that "If a 10 year old Mac Pro can carry your workload, you don't need a Mac Pro, you need a Mini or Studio" is again flawed.
I also disagree that "fast external expansion is more acceptable today".
It's simply that if you use any Mac you have no choice for your storage to be anything but external...unless you're prepared to spend $7000!