In my view and experience it works great for many companies. No massive problems.

IME I’ve worked in offices where at least 20% if not more did absolutely nothing. I mean literally nothing, not that they were doing things that just weren’t visible to me. It has a lot more to do with company culture and performance management than onsite/offsite. I’m not against the idea that the proportion of people who can succeed with remote work is lower, but most of the RTO push seems to be more to do with current management fads than anything else.