> If making my project reduces my power on the project, why would I ever open source anything?

For me, especially when I'm increasing the bus number of something I worked on at work, it's down to two things. Either I'm hoping that my 'power' will remain the same but the 'power' of the project will grow and the new people will take their share out of the surplus.

Or, I want to focus my power elsewhere, and as long as I'm sole proprietor to this project I will be associated with it to the exclusion of other things. It was having my face pressed against glass of shiny new things I was iced out of at work that finally taught me the value of sharing. Indispensable can make you typecast. Deputizing someone has benefits that usually outweigh the costs.