I used to think this. When I was a teenager.
Now I'm pretty sure the fewer programmers you have, the better the program. Don't need to worry about stepping on toes or making sure your parts work with another person's parts if it's just 1 person doing the whole thing.
And if it's 1 person doing everything, not just programming, they also don't need to worry about some manager forcing them to a deadline or requesting ridiculous changes/additions.