CR, I've wondered the same. And, I’ll throw out a theory about it, too. Given all the screens cracking on the M1 MBAs, the squarer, classic MBP, non-wedge shape was needed to reduce the stress on the thin bezeled screen when closed and eliminate the problem. The original MBAs didn't have the problem because the large bezels offered excellent support.
A small percentage, for sure, of the M1 MBAs have suffered screen cracking, but enough to generate a class action suit, a massive 50-page thread even on Apple's discussion forums, many posts and articles around the Internet, and several threads here — one, in the interest of full disclosure, that I started when I was staggered to discover the problem. (See those threads before dismissing this issue out of hand — it's a small %, but definitely a real problem.)
But it could be that both are true — Apple wanting to return to its boxy, outdated look for its entire line rather than to retain its futuristic svelte wedge shape — as well as to eliminate screen cracking.
In my experience, the wedge-shape of the classic MacBook Air series (say, 2013-2017) was far more comfortable to type on than the higher squared off front edge of the MacBook Pros. The MBPs left creases or red lines in my palms and were harder to type on than the MBAs. It didn't matter whether I typed in my lap or on a desk.
I found the 12” Retina MacBooks especially ridiculous and difficult to type on as the palm rests were too short, lacking in depth.
Now, I have large hands and am a touch typist, so that could be a factor in all these judgments.
N.B. The usual disclaimer applies: I'm making no universal judgment about the typing experience or comfort; these are my individual reactions. Others have no problem and even prefer the non-wedge shape.
As the Romans used to say: De gustibus non est disputandum.
