I've been working both as 1-person team for years but also in larger teams for the same amount of time. In my experience the hermit programmer is some sort of a myth. It's true that sometimes tech staff is more separated from more non-tech staff but that is always a management decision because they think it makes people more efficient.

In fact as a 1-person team it's usually necessary to interface much more often with other non-technical people. In larger (scrum) teams that is usually centralized through a PO or PM. Which is in the long-run usually a good thing, pressure can be extreme for 1-person teams since people call the programmer directly. I used to work at places where sometimes for a time frame of 1 hour a day someone tries to make me listen to his or her ideas. Such a waste of time.