Apple should absolutely offer 16 GB on all of their base model machines. It's quite stingy for them to stick with 8 GB RAM, especially given how other competing laptops at spec'd.
THAT BEING SAID, I am not surprised that a lot of people are getting hung up on the base model MBP having the "pro" designation and yet only offering 8 GB RAM base. Apple's marketing is genius, and they've convinced us that any device that is labeled "pro" is for professional users, which we all know isn't the case. Pro users can use non-pro devices perfectly fine in some cases, and non-pro users can of course use pro devices perfectly fine (albeit with a machine that is overkill for their use case). Pro is simply a moniker than the marketing folks created to have product segmentation; it's the same reason Apple has Pro iPhones, iPads, and MacBooks which are all spec'd and priced differently compared to their non-pro / Air counterparts.
But all of these things are so subjective. What defines a professional? What defines a professional workflow? What defines professional specs? I'm an accountant and primarily use email, web browsers, and Excel for my work. I am a licensed professional in my field but my work could easily get done on the base model M3 MBP with 8 GB RAM. In fact, my work could also easily get done on a MacBook Air. Of course, like everyone, I would absolutely love to have more RAM even if I don't really need it. But if there are folks that only want 8 GB RAM and don't care about upgrading RAM for their use case, the base model is perfect. The folks that know they need more than 8 GB RAM likely will not be looking at the M3 chip anyway; they'll be going for the M3 Pro / M3 Max.
I see the base model M3 MBP as more of a competitor to the MacBook Air than the M3 Pro / M3 Max MBPs. It's a great machine for someone that doesn't need the additional power of the M3 Pro / M3 Max chips, but still wants the upgraded design compared to the MacBook Air (better / larger / brighter display, better speakers, better battery life, etc.).
We also have to remember that Apple's best-selling MacBook is the MacBook Air. Despite all of the dialogue on whether or not 8 GB RAM is good enough, regular consumers don't seem to care. Those of us on here are in an extremely niche position where we are thinking about and discussing this topic, whereas the vast, vast, vast majority of consumers will not know and / or not care. For most consumers, they will just get the base model MacBook Air and use it for basic tasks (although even this is subjective), and it'll be perfectly fine. Sure, they would benefit from the additional headroom that 16 GB RAM affords (especially after 5-10 years as memory usage changes over time), but if the RAM is upgraded, the price is also upgraded, and Apple sells less units. I'm not defending that decision, but that is simply the economics of their choices. For that same consumer, if they don't care about the specs but they do want a better display and better speakers, the M3 base model is perfect. They aren't paying additional for specs that they don't care about.
The average consumer really isn't going to care about having a "Pro" vs having an "Air"; based on what we know, they will likely base their decision on price alone. They'll base their decision on things like size, weight, and display as well. Any machine will suit the vast majority of consumers perfectly fine, so they aren't thinking about 8 vs 16.
I do hope Apple updates base models with upgraded RAM soon; I'm sure that even when they do, it'll be 12 GB RAM vs 16 GB. It is an overdue update for sure. However, when it comes to whether 8 GB RAM is good enough for people, I think people really overestimate what the average use case is for Apple's computers, and get too hung up on the Pro name. The engineers are not the one naming their machines, I can pretty much guarantee that.