Because it's near impossible to get an interview at these places due to the number of applicants unless you have an in?
The remaining ones will at least get a phone screen and if they have relevant knowledge and experience will proceed.
Because they will pay more, and/or the work will be better. Because with the current RTO push, it's very likely that the only companies still offering remote work in a few years will be companies that can't get staff otherwise, either because of pay or the work itself.
You already can't get a new remote FAANG job, the mid-level organizations will be next.
Remote positions remain, for the foreseeable future, a sign that allows distinguishing mature and/or modern good companies (probably good enough to pay well) from immature and/or decrepit companies (possibly profitable enough to avoid facing problems) with managers who "need" their pigs in the sty.
Why would I come into an office when I can just apply on a full-time remote position?
Then again I have been full time remote since 2018, and the company I am with now has been full time remote everyone since before the pandemic. There's no office to even go into, so I don't think this is a huge risk for me.