It's more flexible than that. A lot of indies are just one guy, but you certainly see small studios of 6-12 people doing e.g. Kickstarters.
I work in a game studio, I still can't wrap my head around one guy doing it all.
My startup now has about 25 coders doing what 2-3 of us did for a few years. I'm still not sure what everyone does. We are actually moving quite a bit slower these days.