In my experience, remote onboarding is a bit more challenging than in person. Remote work seems to be good as long as you already know what you're doing. But in person seems to help people get up to speed quicker when they're new.

This paired with employees switching jobs more frequently (ie more total ramp up time) WOULD translate into lower productivity.

I don’t say that to blame employees, or remote work. The problem can be solved in more than one way. It’s on the employer to keep their already productive employees. Typically, though, that isn’t done very well (yes, a promotion can be had, but many generally productive employees may not get one and still find a raise outside).

If top talent wants remote work, and longer terms lead to more productivity, then one approach could be to keep existing employees happy vs paying more for new talent.