I would be more productive in an actual office - a private quiet space where I can focus but unfortunately that isn't what I have either at home or 'on site'.
I live alone in an apartment with 2 bedrooms, of which one I converted into an office space. It's easy for me to "commute" and have a separate area for work and switch off when I go into the lounge. It's not so easy for people who are in shared accommodation or in studio flats and so on, or young families in small apartments.
Similarly, lots of people move to work and don't have a social circle yet, so their job is their social circle at the beginning. Of course, you don't necessarily need to move for that job any more, but at the same time if you have, then you lose your only social contact if you have by working from home.
It's not as simple as people make out, there are benefits and disadvantages to everyone.
I'm a big fan but I can only talk from my position which is quite fortunate in terms of circumstances.
I've seen this before, I've been working remotely for a lot of the last 7 years and there's a distinct difference in social dynamics. Even if the people in the office need to use Slack or whatever for communicating, they have their in jokes that they sprinkle in and you can feel a bit alienated or ostracised if you're in a minority of work-from-home employees.
Equally, if some people are not able to work from home, that can build resentment or envy.
So the company culture can be affected by different amounts of in-office vs home-office, every company will have their own sweet spot, but I agree with you, there is no simple one size fits all solution.