Why don't developers or developer organizations just keep licenses and rights to certain codes for themselves.

Keep the rights but freely make it available for everyone to use.

But if a company steps in to make anything proprietary, then you exercise your right to the intellectual property of your code and make a decision for yourself ... either agree and make money on it (because developers need to make a living as well) ... or refuse and with hold the right for certain groups, companies or corporations to use it (and if you do end up in court over it, chances are high that the developer will get money out of that too)