These days we have the advantage of popular open source licenses, and thus there is a strong culture of "if the source is available, it's okay to write improvements and re-release it. In fact, the source should always be available and free to be improved upon.". Whenever I read about software battles of the 70s and 80s I always feel like the engineers of the day could be pretty petty and against improvement and innovation. No, you can't look at my wheel, go reinvent your own one, freeloader!
Agreed. That seems to be a common occurrence in the beginning of any industry though. Take Web applications, for example. While we now have lots of extremely high quality desktop apps (heck, the whole stack really), there are only a relative handful of pro-quality Web applications that aren't proprietary (WordPress, Drupal, SugarCRM, etc) compared to those that are closed (GMail, FeedBurner, Google itself, heck.. almost any major Web app out there).
