[atvcatole]

An example here is that Quake was released in 1996 and the source code released in 1999. Quake 2: 1997->2001, Quake 3 Arena: 1999->2005.

I don't think I've ever heard anyone argue that these releases were negative to ID or the game series.

[ryandrake]

That's what makes "It's our IP" an excuse and not a reason to not release game source, once the game is commercially irrelevant.

I'd like to see an example of just one game that failed commercially due to a company releasing the source code to an older game.