

A) this issue applies to all kinds of software.
B) procuring software is a two-way street … the producer assigns terms by which access is obtained, and you agree to those terms in exchange for that access. If the software is SaaS then if the producer chooses to shut down the service then you are SOL. If the software is provided with a long list of terms via Steam, then you are basically buying SaaS with local caching and execution. Maybe don’t reward producers by agreeing to one-sided deals like SaaS?
This kind of headache is what prompted Richard Stallman to come up with the idea for the GNU license. Maybe you think that is too radical… but maybe imposing your ideas of what licensing terms should look like on (only?) game developers is radical also.
For the same reason I think software developers have the right to choose to release under copyleft, I think they have the right to release under SaaS or copyright. I don’t think it is fair to take those rights from them. (I may choose to avoid SaaS or other proprietary models where possible, but I am not pure about it… I just do so recognizing that proprietary tools are a band-aid and could become unusable when any upgrade or TOS changes.)
As one example, keep in mind that some governments may choose to punish a software developer for making “offensive” (by whatever their standards are) content, and rather than fighting a losing battle in one jurisdiction so you in some other jurisdiction can keep using that controversial software the developer may just choose to cut their losses and turn it off for everyone. If you force them to release it anyway then said punitive government may continue to hold the developer responsible for the existence of that software.
There are rights and responsibilities associated with a proprietary model… and IMO you (and your permissive government) should not be overriding those rights for your own short-sighted benefit.