As platforms evolve, old games become unplayable. Open sourcing them will help us preserve them for future generations.
A lot of old games have become unplayable on modern hardware and operating systems. I wrote an article about how making games open source will keep them playable far into the future.
I also discuss how making games open source could be beneficial to developers and companies.
Feedback and constructive criticism are most welcome, and in keeping with the open source spirit, I will give you credit if I make any edits based on your feedback.
Your nostalgia is a bad reason for starting anything really. Most hopefully you won't push your nostalgia on your children and force them to play outdated games.
It would be great if game developers would open source games when they sunset them, sure. But also this might make it impossible for them to make a remaster of the game and sell it.
You mention doom. But this is a 0.1% case. Thousands of games from that era vanished not because you cannot run them on modern hardware, but because they're utter garbage by modern standards.
https://dos.zone/ exists, and you can play a lot of iconic games in your browser. What's exactly the player count there? And those are the best games from that era.
Your nostalgia is a bad reason for starting anything really. Most hopefully you won't push your nostalgia on your children and force them to play outdated games.
It's a dark path. Next you might start making them watch outdated films, maybe even reading outdated books. Before you know it you're teaching them pre WWII history and Newtonian mechanics.
History is important, although more recent history books have better evidence and data than old ones. Literature, generally, ages well, although it's mostly survival bias. A lot of it perishes without any loss to the society. Movies sorta age well. Again, only some. Games don't age well.