I’ve been pondering this. In many ways “hybrid” is the way to go actually. The best of both worlds. Not 3 days a week though—two. Three is unnecessary and one is not enough. Two is optimum.
Amazon owns their headquarters office building. It was constructed to meet the office needs of X employees who work in the office five days a week. If the company adopts a business model in which employees work from home two or three days a week, then it is effectively wasting all that office space that will be unused 40% to 60% of the time it was originally designed to be used.
This is why I only see two eventual options for work that can be done at home: either 100% work-from-home or 100% in the office.
If we're talking about office workers, yeah, two days of mostly useless back to back in-person meetings and 3 days to actually do the work you just wasted two days talking about that could have been resolved with an email or two.
I retired a couple of years ago at 50, but still do gig work for sh*ts and giggles during the Winter months for a former client (big corporation). The nonsense that goes on - especially since they went SCRUM - ah well. It's money for more toys for me to play with all Summer and Fall.