The same people that go for an 11 AM yoga class will stay working until 11 PM because they can and are encouraged to.
Second, and another commenter points this out, the desirability of anyone that lands a job at a FAANG means they get away with it. They have Made It, they are the 1% in their field, and they can go anywhere else outside of SF (internationally if need be) and instantly be hired as CTO of any company. Generally speaking. And of course switch to the other FAANG, possibly getting even better compensation and perks and a better 11am yoga teacher.
Second, and another commenter points this out, the desirability of anyone that lands a job at a FAANG means they get away with it. They have Made It, they are the 1% in their field, and they can go anywhere else outside of SF (internationally if need be) and instantly be hired as CTO of any company. Generally speaking. And of course switch to the other FAANG, possibly getting even better compensation and perks and a better 11am yoga teacher.