Proprietary software is about as good as open-source software. There are so many problems with proprietary technologies, however, that I'm beginning to think it's best to avoid them:
The software will only be maintained as long as the company exists (and profits).
The level of security of the application is as unknowable as the source code.
Alterations and derivative works, however necessary and beneficial, are disallowed.
I simply don't see any point in even learning to use such systems as those created by Microsoft and Apple. Of course I don't pretend that ignorance is the superior option: one has to have a certain working knowledge simply because of the ubiquity of these things. I just don't see any reason why, as an independent developer, I should ever consider it a remotely good idea to actually use them.
So that's the question, or discussion topic, or what have you:
In what ways do developers benefit at all from using closed-source development software?