>25+ years ago, when IBM ruled the world of 'data processing' and ALL software was proprietary there were programmers even then who were modifying the source and freely distributing it. The source was provided because, often, the only way you could get by a bug promptly was to do it yourself and then wait for the 'official' fix later (often your own, sanctified).

That is a good point and one I hadn't considered.

Though... if you have a company that uses a closed source OS and one that open source OS, but the open source company devotes part of its time to improving the OS, then the closed source using company will be more productive in terms of doing their core busines since the other is fixing infrastructure.