Valve also has shipped exactly one first-party game since Dota 2 in 2013, outside of VR stuff, and it's a card game. I don't think they're tops on the list of studios that could give Google a big hit game to put on their new cloud console.
But I'm also happy they haven't. These cloud streaming ecosystems are the apex of locked down closed systems. Valve is built on a culture of modding, revving games to make new ones, and being fair to users in a way that doesn't compromise being fair to developers. Cloud streaming systems, by and large, are not. They're built by big-tech megacorps that are looking to buy-in then cash-out on an industry they know nothing about (except Nvidia; if there were one cloud streaming service I'd support, its theirs. Nvidia isn't perfect, but its definitely within their wheelhouse, not a cash grab).
Beyond that, you're marginalizing Valve's dominance in the gaming industry. Of the top ten games by players on Steam right now, again, the most popular western gaming platform ever made, three are made by Valve (CS:GO #1, Dota2 #2, TF2 #4, and #3 is Rust, the monthly TwitchFad). Overall, the only non-Steam western PC games which compete with their numbers are Call of Duty, League of Legends, Valorant, Fornite, Minecraft. The one theme with most of these games is that they're pretty old. People love games they know; when the developer sticks around, builds out a fair monetization scheme, and iterates on the gameplay, the games become unbeatable pillars on whatever service they're distributed on (the few that aren't old: Fortnite/Valorant will get there, and CoD has this in a way, but is definitely the most different every year). Valve is a rock-solid game developer; the fact that they don't release new games every year just speaks to their commitment to their existing communities.
And, they also made Half Life Alyx last year. Its legitimately the most groundbreaking game to be released in the past decade, that unfortunately so few people are able to play. You physically cannot play that game and not have a shit-eating grin on your face the whole time. It is the only game I've ever played in VR (on Valve Index) that made me think "if this game were in both non-VR and VR, I would choose to play it in VR".
The first was well received but died off the rest of auto-battlers, the second was terrible but is being reworked, and the third was critically acclaimed and the probably the most important VR game released besides BeatSaber. I know you said not counting VR but I feel like skipping Half-Life:Alyx, a game in a well beloved franchise that was very highly rated, is a little disingenuous
Besides that they've also: Trialed Linux-based Steam Machines Greatly contributed to Linux gaming through Proton Tested out two unique hardware systems (Steam controllers and Steam link)
Outside of them being essentially the biggest and most important game distribution service, as well as helping devs with any distrbution, multiplayer, DLC, etc services that they need.
So I'd say it's a toss-up between whether that would benefit Google or not.
How? Stadia doesn't support VR.
And a massive failure at that.