Control freakery is the reason why. Also the reason why at one company I worked for, the rank and file were in huge open plan offices, screens always visible. Senior management had private offices with doors, and every single one of them had screen facing away from the door.
Many people work very well remotely. Others use it as an excuse to slack off. I did it for two years during Covid, and previously for a year doing different work. I never worked harder or more diligently, but that wasn’t true of everyone.
I’m retired now, but my husband still works; and he’s finding that some people got so used to telework that they resent being in the office now and use every excuse to get out of real work.