While I don't fear for the games I either own physically or which are widely available digitally (some will be forgotten, sure. But if you love them, you can collect them). But games as a service will be and are constantly lost. Basically everything that relies on servers or is massively multiplayer is only available for a couple of years at best. And few of those even allow for fan hosted servers anymore nowaddays. And they constantly change significantly. E.g. You just can't play the original League of Legends or PUBG anymore. Those worlds and games are immensely popular right now and at the same time already lost forever. Whenever a new patch changes something major or a map gets remade, that experience isn't the same anymore.

So I guess: play solo games from local copies of some sort and chill to avoid the problem? ;)