This assumes that WFH is equally as productive as in-person for all companies.

Some companies may have conclusively determined that for them, in-person is far more productive than WFH, and so losing certain applicants is an acceptable tradeoff.

As an anecdote, a friend works on a team that does a lot of hardcore low-level algorithm development. They require at least three days of in-person each week, since collaboratively doing math on whiteboards just doesn’t work as well over Zoom.