In the long run, software development is not economically sustainable without a legal obligation to pay for its maintenance.
That means software development done for fun / for free, paid for by taxes (directly or through universities), or some kind of copyright.
The most popular strategies, right now, are (1) proprietary software, (2) proprietary software with free components, and (3) selling the right to use free components in proprietary software.
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Even *most* "open source" advocates - including the OSI! - are perfectly happy with this situation, and see violating your user's freedom (directly or indirectly) as just what you have to do to make money.
