> but I think BSD (permissive for developers, maybe restrictive for users) vs. GPL (restrictive for developers, permissive for users)

Strawman. MIT/BSD is not restrictive for users.

When someone derives from my permissively-licensed code and doesn't share back with me? Not my problem, but theirs. They now have a legacy fork to refresh every so often at some non-trivial cost. If I'm maintaining a codebase for them to contribute, then they might be better off contributing. If my codebase is their secret sauce, well, good for them -- perhaps they should consider paying me to help them, and they are welcome to try, but it's not a requirement. It's all good.

Now, if I'm building a project to monetize, I might not open source the secret sauce. The GPL wouldn't help me there anymore than BSD/MIT. So, what good is the GPL to me?