> If social isolation during work is the default, people will have fewer friends, because making friends takes more effort.
I disagree. If these people were making friends by just being at work, they wouldn't be feeling so lonely right now. They would already have plenty of social connections that would not just evaporate because your not in the office anymore. Even those just entering the workforce should have these friends from school. Instead constantly being around people at work makes people "feel" less lonely, hiding the fact that they haven't actually made a deeper connection. Shoving people back in the office will just hide it again, it won't fix the problem. It'll just decrease the quality of life of everyone who happier right now. On the other hand leaving things as they are and instead supporting those feeling isolated in finding other outlets lets the majority of people keep doing what's working for them, and the rest are likely have motivation to fix the problem.
The issue is finding friends after relocating to a new area. That's easier for some and harder for others. With coworkers, you already have a pool of people to spend time with. Through them, you can meet other people and learn about activities that are available in the area.
Furthermore a read through the comments on this thread make it pretty unambiguous that the problem is not restricted to people new to the area.
If social isolation during work is the default, people will have fewer friends, because making friends takes more effort. They may be satisfied with their situation, because they contrast the outcomes of having more friends with the effort needed to make them. But the entire society may be worse off than a society where people have more friends because working with other people is the default.
Fundamentally, everything based on the idea that people should make different choices is doomed to fail. To make the society better, you must work on structural level and change the defaults.