Now if a shoe only works for a week, I'm not going to buy it. If it works for a year, sure I'll take it.Similarly for a digital good (phone, computer, software) we need to come up with a baseline on what the acceptable number for life is. It cant be Infinity, but it should be reasonable.
This all ties into ownership. If I own something I have control over it, so I can re-sell it if I'd ever like to re-coup some value or let someone else make use of it. I can lend it to a friend, and have it back to use or lend again. I can give it as a gift to a friend or family member. I can keep it indefinitely as a memory. All of these are reasons why some people still have a NES, GameCube, etc. It's probably not that they've been playing on the console for 30 years. They either kept the NES they owned as kids, or bought one second-hand for the nostalgia, or got it as a gift from someone who knows how much they like classic games, etc.
There are still have tournaments for games on old consoles. Old games are perfectly good games— they don't have the same wow factor, but they are as fun today as they have always been. Will future "classic games" be lost to history, or available only when a publisher decides to monetize the nostalgia of the public with a re-release?
The better analogy is: when you buy a book, do you expect you can read it again in ten years? People who bought 1st pressings of Beatles albums 60 years ago can still play them with their grandkids. I can still play old SNES with my siblings at Christmas. But imagine a 2019 being unplayable in 2029. It's reasonable to be concerned.
Mario Kart on the Wii still works. Online play is broken though because Nintendo has no interest in running old servers to keep a service in a long discontinued game running.
If any games are developed solely for Stadia, will they disappear if the platform disappears? Even if it doesn't, will they be playable in perpetuity, or will Google shrug breaking changes if it's for games that are over N years old, and have under K users?