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.
Lets be realistic, companies won’t want to make it open source because they think it will lead to a loss of revenue (there is a mindset of “never work for free”). openttd basically led to loss of revenue because now that there is a open source version (even the assets got re-implemented) people that are playing that are not playing proprietary games (including the proprietary original version).
You might argue there is no significant loss, but i don’t think you can prove that especially to the people who own the companies which include pension fund managers who only care about the profits because if they will underperform people will go to some other pension fund or invest in other stuff like real estate.
A source available license is a more realistic option , You get the source code and permission to improve it but still have to pay something to run the game.
You could do open source engine, proprietary assets. Like the original doom 1, 2, and 3. You can get the engine for free, but have to pay for the art assets.
https://en.m.wikipedia.org/wiki/List_of_open-source_video_games#Open-source_games_with_non-free_data
Only if they still sell the assets.
I’m in favour of also dropping any copyright and intellectual property protections the moment a company stood selling the game. They evidently have no more commercial aspirations for the title, so it doesn’t need any protection from technically feasible copy protection circumvention methods.