I don't necessarily agree with that - many people/companies build frameworks for primary use in their own work that they open-source as a courtesy - with benefi

I don't necessarily agree with that - many people/companies build frameworks for primary use in their own work that they open-source as a courtesy - with benefits of course, more eyes make shallow bugs, advertising, etc. e.g. Github employees probably (originally) wrote ReactiveCocoa and Carthage because they were useful for developing Github apps, not necessarily to gift fantastic tools to the iOS world.