Small teams can be super productive, but unless the people in it are there for the full run of a product, you'll end up with a problem; taking over the work for one developer will take more than one developer.

I'm sure - but haven't witnessed this myself yet, so take it with a grain of salt - that if one productive developer builds an application in a year, it needs a team of 5-10 to continue development at a similar level, and even then it may not make it.

Companies need to focus on keeping software as simple as possible, well documented, and transferable. Unfortunately this also means curbing people's enthousiasm.