> I really wish more games shared the source, even if it's under a restrictive license. It's just interesting to get a peak under the hood.

technically true, but the risk of tainting FOSS projects to the point they can be killed by corporate lawyers could be too high. What if a FOSS developer implements in perfect good faith an algorithm that shares some resemblance to a proprietary shared source piece of code they just studied two months before? Could whoever owns that code have enough grounds to send a c&d to stop any development if not attempting to take ownership of the project? Not sure if I'd like to test that. As much as I deeply dislike closed source, I'm convinced that having a firm distinction between open and closed helps to avoid some dangerous grey areas.