Steam is discontinuing official support for Ubuntu
Steam users that run Ubuntu may need to start thinking about alternatives to one or the other in the relatively near future.
Valve developer Pierre-Loup Griffais posted on Twitter that version 19.10 and up of Ubuntu will no longer be officially supported by Steam. Valve will also no longer recommend the world's most popular Linux distribution to its millions of users.
This move is likely due to Ubuntu soon discontinuing support for 32-bit applications, which Steam itself and, arguably more importantly, Wine, are. This compatibility removal will therefore remove support for Steam Play via Proton, software that has opened up opportunities for Linux users to play games previously exclusive to Windows operating system users on PC. Even if Valve were to create a 64-bit version of Steam itself to maintain compatibility with Ubuntu, the loss of Proton and Steam would result in a huge loss of potential library for Linux users, so much so that it arguably wouldn’t be worth it.
In any case, Valve’s gaming-focused Linux distribution SteamOS will remain supported and updated for the foreseeable future, and other Linux distributions that continue to support 32-but applications should be able to run Steam, Steam Play, and Proton just fine. In addition, the company is also "switch[ing] [its] focus" to an as-of-yet to be determined Linux distribution.