In my experience it can work quite well. I work alone on many projects. Given, you need support staff. I have someone to document everything aside from the most technical parts that I need to write myself. Also a project manager that extracts requirements and expectations from customers. Doing that myself would increase project duration tremendously.

It is pretty common in the embedded world in smaller companies. There just aren't enough developers to render enough support.

The problem with one-man-shows is the dependability. A lot of web developers go that route. But if they are unavailable because of private stuff or illness, the project they are working on is basically iced.