The problem is that SteamOS doesn’t have a whole lot of boot options besides “start up directly into Game Mode successfully”. If Steam chokes while ingesting any of its config or any metadata in your library, that’s the end of it. You can hold a button to wipe everything (the Playstation solution), or you can figure out how to boot a live-iso and fix “the problem”. Not everybody has the skills to fix stuff in Linux, heck not everybody has the ability to “boot up from a usb stick and have a working keyboard, using only one USB hole”.