Many reasons but to give you one that I haven't seen mentioned before: After going permanently mixed remote our company has reduced the office space. This means that we now have flex seating. It sucks and I really miss having my own desk.
My point is that even if I can choose it's just not as nice as before so I certainly hope some companies will revert. Remote work is simply not for me and I want to work at a company that doesn't have these drawbacks. I want to come into work, have my desk and know who I will meet there every day.
I think there are mainly two camps of people. Those who prefer remote and those who prefer onsite. Both perspectives are perfectly valid. Ideally, companies would put more focus on what their employees actually want instead of just creating policies. Work life would be easier if there were teams of remote enthusiasts and teams of onsite enthusiasts (and maybe teams of mixed mode enthusiasts), rather than teams where about 50% don't like the current mode.
I fully agree with that. Some companies should go fully remote, some mixed and some onsite. It would however need to evolve over time with employees moving to the type of company they want once things have settled down after the remote chock of the pandemic.
I just hope that there will be companies that are fully onsite and proud of it. Now they are getting shamed for it even when there are people like me who wants to a work at such a company.