It's a thing. My employer (Dropbox) has mandated it, for instance, and no longer has offices at all.

Was that before or after COVID ? Because Gitlab for example was always remote by principle. We are talking here about companies that were mostly in large offices in the first place.

Very much after.

Surely they have some offices? As a small company that has no offices, I actually run into problems at times because we don't have an official office address. For example, some financial and other types of companies want things like a copy of an office lease or a utility bill in the name of the company.

Probably not an issue for a public company like Dropbox. I suspect they have an official address and SEC filings ought to demonstrate they're real as much as an office lease.