I'm surprised and baffled by the amount of misconceptions about open source software in this thread, so I hope you don't mind when I try to set the record straight on a couple of subjects.
Commercial software is not released as open-source. That defeats the purpose.
Actually there is quite a bit of commercial software available today that has public source in one way or another. Having source code free for download does not imply you do not need a license for a product or that you're able to repackage and redistribute it. It all depends of the license the code is published under.
That being said, there are a lot of commercial software vendors which have opened the source code of their products or parts of their products available as open source. Oracle, IBM, Apple, Microsoft, … all have projects which offer open source.
Yes, but often commercial software (which is still being purchased etc.) have older versions availiable as open-source.
For example?
One example of a company which open sources its obsolete technology consistently in the gaming industry is ID Software, well known to everyone from the Doom and Quake series of FPS games.
The main advantage for them is that their older games never die, adding to the momentum of their achievements. ID Software has long since stopped developing these older engines, and without the help of the community picking it up, these games wouldn't be playable on present day computers at all. To this day, its still possible to play Doom and Quake games, with the oldest games moving towards the 20 year mark, on a modern computer.
If that was open source and people would iron out the bumps and wrinkles, I would think there would be little reason left to get gm8.
They could also incorporate these fixes and changes back into their main code tree, and end up with a better product as a result. It could also facilitate their products being ported to and extended for platforms which yo yo games themselves do not deem commercially viable, or for which they simply do not have the resources available to develop for.