Among the remote-only companies that I've been in, I've never seen the remote-culture as being in any way problematic. (Quite the contrary. They were usually better at communicating).
The thing is that, in many cases, there is no "all-onsite" especially for larger organizations.
Your field people (sales, system engineers, etc.) are going to be wherever your customers are.
Acquire a company in a different city? If you force everyone to move, you're probably going to lose a lot of the value of that company?
Work with open source software? Many of the upstream developers are going to be scattered all over the world in any case.
And as soon as you're in multiple locations even within a given city, you're really not much different from being in two separate cities at that point.
Certainly, there are challenges. But I'm in a very mixed environment, which I think generally works pretty well.
To be honest, the situations where I have personal experience are mostly more senior teams where everyone is doing a lot of travel anyway, a decent percentage are fully remote and the rest are often only in the office a few days a week. And everyone is doing as much communication (if not more) with other teams and people outside the organization as they are internally anyway.
You're probably coming out of an environment where you spent lots of time with lots of different people. Played sports with them, partied with them, studied with them, etc. Now you're going to spend your days in a possibly cramped apartment communicating over chat.
You're less likely to have the discipline or the experience to work on your own.
You may not have much of a separate social group where you're now living.
Obviously, everyone is a bit different. But I know I'm pretty happy to sit at home these days. I'm sure I would have hated it when I was starting out--and wouldn't have been nearly as effective.
It's both effectiveness and preferences. I was just having this conversation a couple of days ago with someone whose company location is basically out of space. I asked why more people don't just work remotely. (Many already do; the company is generally remote friendly.)
His response was basically that there are a lot of employees, especially younger ones, who would probably up and quit if they were told they had to work out of their homes. Most of the people who haven't already gone remote either have to be in the same office or want to for whatever reason; this is in an area where housing is fairly reasonable and commutes are fairly modest.
Leaving aside that I started work at a time when communication tools were much more limiting than today, I still can't really imagine working from my apartment during the early years of my career.