If the company is still succeeding, then it doesn't seem to be an unreasonable move. The company doesn't operate for the benefit of employees commutes. If they can still attract and retain talent and have a more practical work space, then great.

Any company/CEO who wastes 45 x 2 minutes of my life on a commute is bound to get a quit notice.

A company that isn't either all-remote or encouraging of significant WFH is going to satisfy some people and not others with respect to commuting.

Then they'll get people who live closer. Like I said, their business isn't built to give employees short commutes. Certainly retention is in their interests, but it's a means to an end. Moving their office is also a means to an end.

Then why'd most of them leave?

Because the company was staffed by those developers already happy working in Palo Alto, obviously.

I'm just speculating that there may be more developers who are happy with the East Bay location in the wider pool of developers, not that this was a good move for the then current employees.