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?