Overall great analysis from the OP, now as to why Apple isn't doing more:
Delays are not intentional, no one at Apple is sitting on products waiting to release it for some arbitrary reason, sometimes things like M2 just get delayed, so sure they could improve that but thats also like saying they should not have bugs in their software, everyone knows this, actually doing it is much harder. Also, I believe 1.5 years was always the plan around updating Mac silicon vs the annual iPhone update since they know people update Macs slower than iPhones, so then they can focus on bigger jumps anyway.
To me the main issue is Apple is not concerned with market share, they're concerned with profitability. Their pricing maximizes profitability at the expense of market share, something they are quite willing to accept given their overall dominant ecosystem. Sadly the days are gone when Apple was really trying to prove itself (and save itself from bankruptcy) and gain marketshare in those years when Jobs came back.
Still, the Mac is the best its ever been, apple silicon is amazing, marketshare is up overall since apple silicon, and I'm pretty happy with all that. It's just pricing that keeps these from being as disruptive as they should be in the overall industry, and agreed, that is frustrating.
And of course all the other points people have made about businesses just buying whats on contract or people already bought M1 waiting to upgrade etc. are valid, so there may be some logic to Apple's pricing after all, maybe they would lower it and marketshare would not change drastically, I'm not sure, but as for us the loyal fans, some of the pricing certainly seems outrageous which I think hurts Apple long term.
It seems even small tweaks would go a long way to improving the customer relationship and brand so people like us are passionate about recommending them to our friends and family no matter what, rather than saying, well they're great, just don't upgrade the storage or RAM too much or you'll need to sell your kidney.