A reasonable requirement would be having the server code, data, and assets be released to public domain when they shut down the service. If they're not operating it, I don't see any good reason to allow people to squat on content that people want to run for themselves. A year after the last commercial offering is sufficient time.

If you run a SaaS and then shut it down, game or otherwise, then you should have to release that software under a permissive license, or to the public domain, along with any non-code assets necessary for functionality equivalent to the last commercially offered state.

The world would be better, we'd end up with fewer leeches and rent seekers.

By selling software, the developers benefit from the protections of copyrights. Mandating the release of source and assets after the end of commercial activity benefits society. This would require government to work with an archive organization of some sort - maybe offer tax incentives to any site that freely hosts said content, for up to 5 years after the release.

There are all sorts of valuable things we could be doing that benefits society and individuals instead of making it all about ruthless corporate bloodsucking and maximizing markets.