It's complained about most (probably along with SSD) because the RAM specs on MBPs are increasingly below par - and the upgrade prices are sky high - compared to competing computers (i.e. premium ultra-portable laptops cisting >> $1000)... and the defence is always "8GB is enough for many people". It's far less common to see anybody saying (for example...) "M1 is. good enough for most people" - yet it obviously is because millions of people are happily using M1 (and even older) machines and the second-hand prices keep holding up. My question is - what's so special about RAM that makes some some people so keen to defend 10-year old specs, when everything else has improved?
In answer to your question, again, people particularly defend 8GB RAM because people particularly complain about 8GB RAM. If people complained about 500 GB storage, people would defend that too (and I'm sure that happens).
Personally, I think the whole debate about base specs is pointless. Not only because it won't change anything, but because there can't even be a debate "winner". No one here has done the market research nor knows the insides of Apple to say with any authority what should or shouldn't be. It's all pure armchair economists and CEOs going off nothing but bits of surface level information and their own biases--which I'm sure they'll say is enough to have an authoritative viewpoint. Armchairing is fine for fun, but if it's seen as anything more than that, things quickly get delusional. And when people say Apple should do this or that, I don't even know in what terms they mean. Morals? Economics? To me, it's simple--market forces should determine what Apple (and every company) should do--and for the most part it does.
But I have no problem with people complaining about price. It's understandable and people are allowed to vent. But this complaint over base specs often bothers me because it's really just a roundabout way of complaining about price. The better spec is available, the complainers just don't want to pay for it. Again, that's totally fine if they think it's overpriced. But my main problem is when people start making baseless claims about what "most people need" in order to try to make their want look like an entitlement.
And yes, the defenders shouldn't say "many people only need 8GB" as a hard fact either (depending what they mean by "many"). But the latter is more likely true, simply because it wouldn't make much sense for Apple and other companies to sell 8GB if there wasn't a decent market for it. If they do switch to 16GB base, that will imply that the market for 8GB is no longer decent. But that's only circumstantial evidence, so it's not hard fact, just an inference.
Er... except, for the last couple of iterations, Apple have been offering an old-model MBA, with the previous generatoon of processor, as the cheapest MacBook - and presumably selling them by the bucketload. Quite likely that they'll do the same when the M4 models launch - either the current "better" M3 MBA or perhaps they'll just keep the M2 (just as they've kept making M2 iPads) - and probably still with 8GB RAM even if the Pros start at 16GB.
Plenty of people still happily rocking their M1 MBAs which were already overpowered for "presonal productivity" tasks - if Apple offered a cheap new-old-tech laptop the problem would be unlikely to be that it wouldn't sell, rather that it would eat into sales of more expensive MacBooks and iPads.
You said "There is a large enough market for which a M1 would be enough, or 6 hour battery life, or 4 cores, or a lower-res display, or where Thunderbolt 4 is not needed"
And I said, Apple doesn't sell that so there probably isn't a market for it.
Yes, Apple does sell M2 (one previous generation) with better specs than what you listed. But I'm honestly not sure what point you're making here.
Not while the "Pro" name is attached to a particular, well-established spec and price point in the Mac range.
Sure, "Pro" and "Air" are just name tags that Apple could decide to use differently in the future (heck, the original Air was more expensive than the Pro, back when such a thin computer was a much bigger deal and the tech more expensive) but right here, right now, the Air is the entry-level and the Pro is the "better" model with better screen, more connectivity, active cooling etc.) - and there are no rumours of that changing anytime soon.
What? This is Macrumors! Of course people here would complain if Apple re-badged a MBA as a MBP. They'd be complaining about the confusing branding rather than the price but they'd rightly be pointing out what a stupid and naming scheme it was. People are already complaining about the confusing dumpster fire that is the iPad range (where Apple really can't decide what "iPad Air" means)...
Sure, people would complain about the name change because people here like to and will complain about every little thing, but that doesn't mean everything is actually an issue. The people complaining about the price of Macs would be too busy happily buying this cheap Mac to truly care about the name change, not in any way close to how they cared about the price.