Valve Will Not Be Officially Supporting Ubuntu 19.10+
He tweeted late Friday night, "Ubuntu 19.10 and future releases will not be officially supported by Steam or recommended to our users. We will evaluate ways to minimize breakage for existing users, but will also switch our focus to a different distribution, currently TBD."
We'll see how this plays out. I'm hearing that Canonical may revert course and provide limited 32-bit support, but that isn't yet confirmed. We'll see if this also leads Valve to renewed efforts around SteamOS / Debian or if they simply decide to shift resources elsewhere. We'll see how this plays out.