I’ve been to NYC, SF, Seattle… all that closeness (I called it cramped and stifling) was not something I would want to experience long term.
[1] https://www.youtube.com/watch?v=MWsGBRdK2N0 [2] https://www.youtube.com/watch?v=bnKIVX968PQ
Not Just Bikes has some good video of places in the Netherlands and elsewhere that come close to meeting the ideal. Take a look too at maps of small/medium towns in Germany or Japan compared to USA.
Let's hypothesize about a utopian city where a person's housing is, at a maximum, a quarter hour walk/bike from their job at Apple. The moment that person switches jobs to Google, however, they have to choose between moving or losing every benefit the utopian city layout has provided. Worse, their new commute would be explicitly working against the design of this hypothetical city.
Workforces should not be (and are not with suburbs) tightly integrated into where they work. This is something important to consider. You can't have the same density of employers that you have today if you're also packing in the other services (residential, markets, drug stores, laundrymats, etc).
Even with a commute, riding a bus or train is much less stressful than commuting by car. You can read a book, reply to emails, etc..