ID software, of DOOM fame, used to release all their games as shareware. and 7 years later release the source.
just last week someone got sued by Microsoft or EA (dont really remember) for running a game server they reverse engineered for a game they don't even support anymore!
They weren't sued, they got a letter from EA telling them to stop using EA trademarks and to stop distributing the EA client software. The letter[1] said nothing about shutting down the servers themselves.
It was rare then, it's rare now, but it does feel like it might be dwindling. Before it was just a matter of talent and ethics. Now it's a matter of talent, ethics, the scale of production, and the possibility of massive payouts by embracing LCD tactics.
— Douglas Adams, The Salmon of Doubt
Games cost a lot of money to make. They're part of large international brands. There's a lot of stake holders and a lot of money on the line. I don't really blame publishers and developers for being cagey with that sort of IP.
I think that games that enter a more open space certainly have a longer lifespan. DOOM will be around probably as long as humanity just because the code is available and it's a fun game. But that long term thinking doesn't keep the lights in the studio on and doesn't help with the ever increasing complexity of game development.
I don't think we need to be so doom (heh) and gloom about the state of software as a whole.
My general opinion on this is that AAA gaming studios have become too large and gangrenous. Indie gaming, however, has been enjoying an incredibly excellent period recently, which keeps my spirits up.