The problem with paid proprietary code is that it almost inevitably devolves into a bloated mess of haphazard features being tacked on year after year by contractors who don't care about how hard it is to maintain, and don't even care if it works well because they don't need the code themselves, and the people buying the code don't use it, because they're buying it on behalf of a company and the people who actually use it just have to suffer through it.

I think the one thing that would help open source more than anything else is if we outlawed contracts where the employer owns all copywritable material created by the employee.