> How much progress could we make if Steam deprecated their runtimes, abandoned containerization for new games, and let all new games just use the native system libraries? How loudly do you think gamers would complain if a distribution upgrade broke their favourite game?

If the steam runtime didn't exist, most gamedevs would only target the most popular distro - probably the current Ubuntu LTS, and you would have to recreate the runtime on your distro of choice.

And once there's a new Ubuntu release you would also have to recreate it there (or the game updates and now you'll have to recreate it on the now-old version).

The choice isn't between steam runtime and a utopia, the choice is between the steam runtime and something much worse. Linux libraries simply aren't stable enough in API and ABI.