Given the massive collection of titles on Steam, now that even EA has decided to make a comeback, Valve's gaming distribution platform certainly isn't short on developer support and would only need them to be legally on-board if it decides to compete in the cloud gaming space.
This indeed is what Steam Database (SteamDB) discovered in a Github release on Valve's partner site code, stating that they (partners) "must agree to the terms in the Steam Cloud Gaming Addendum before continuing," leading many to believe that Valve could be working on a new cloud gaming service for Steam.
Valve is working on "Steam Cloud Gaming" according to partner site code update. Partners will need to sign an addendum to their terms.— Steam Database (@SteamDB) November 6, 2019
Could this be a competitor to @GoogleStadia?https://t.co/7AQ9YxCol8
The company already has Steam Remote Play, Steam Link Anywhere and an upcoming feature called Remote Play Together, that brings online support to all local multiplayer games, but all of them require a local server (namely your gaming PC) to function.
A 'Steam Cloud Gaming' service could potentially end up being a Google Stadia or Microsoft xCloud competitor, where Valve has its own gaming hardware in data centers that allows players to stream titles from their Steam library onto supported devices (smartphones, tablets, laptops/PCs).
Valve has not made any official announcement regarding Steam Cloud Gaming, but if it does intend to offer such a service, it would need to consider latency concerns (among others), particularly for competitive gaming, which its community (that's slightly more demanding than others) expects to be addressed.
Then again, the company could be looking to expand its playerbase and business, with users looking for a more casual play-anywhere experience that cloud gaming promises, and not be left behind in this space.