We're seeing more reports of Steam for Chromebooks coming and Luke Short writing for Android Police thinks it will be soon. This would be a long time coming, after we've seen hints of it appearing for over a year now.
It won't be particularly helpful for a lot of the lower-end devices, but Chromebooks have been steadily getting bigger storage drives, with newer processors too that are much more capable. The new system that makes all this work is named Borealis, and it appears that as of November 29 it gained new "flags" regarding a Beta mode and a way to disabled "ChromeOS-specific integrations for the borealis client".
Not only that, there's also an earlier one from November 24 that mentions Borealis gained "support for Proton and SLR versions in Borealis game reports". Based on that wording, it appears they might have their own game compatibility database, which could end up looking something perhaps like Deck Verified for the Steam Deck.
Since Chrome OS is a Gentoo Linux-based operating system, it's another way that might help push up the Linux numbers on Steam. Although, it's possible Valve might tag it specifically as it's own thing since it's not really a "normal" Linux distribution, regardless, it will be running Linux native games and Windows games through Proton so it will still help Linux gaming as a whole.