system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why don't game developers release old games to be bought and downloaded?

There are a number of games I'd spend money on and yet they cannot be bought and downloaded.

Why is this? Is there a cost to doing it? 

Edit: consoles make sense but what about PCs?
gpt
Old games are built on old platforms and need to be re-engineered to work on modern platforms. Game devs do release old content all the time. You can go on your phone right now and download a ton of Square Enix's old games that have been ported to Android and iOS, but there has to be a financial incentive for them to do it.