You have some good points. It won't be easy. However, most DAO's the creators of the DAO usually hold the most tokens/voting rights. The DAO itself can be deployed in several different structures which will take a few first movers to lay the framework for what works well. Regarding payments it could be pay to vote or other models which I have seen out in the wild in Web3.

I can envision a proposal mechanism which pulls funds from the DAO pool to fund development for a specific feature.