According to Axios, both The Quarry and High on Life, an upcoming FPS from Rick and Morty creator Justin Roiland, were originally key components of a deal between the games' publishers and Google, which at the time was trying to beef up the Stadia's catalog of streaming games to attract buyers. It isn't stated explicitly in the report, but it sounds like Google had every intention of making The Quarry and High on Life Stadia exclusives.
Of course, ultimately Google would shut down its first-party exclusive games department following lukewarm critical and commercial reception. This opened up The Quarry and High on Life to other, more traditional buyers, and now the former is available on PlayStation, Xbox, and PC, while High on Life is due to launch on Xbox and PC sometime this October.
Axios's report offers the most concrete insight at what could've been had Google Stadia been more successful. A VGC report from February 2021 claimed Kojima had been working on an episodic horror game for Stadia, but Google quickly denied that report, saying it "reported hearsay as fact."
Indeed, had The Quarry been launched as a Stadia exclusive, even for a limited time, it almost surely would've incentivized folks on the fence about the streaming platform and boosted sales somewhat. Supermassive's latest has been generally well-received, with our own somewhat dissenting 3/5-star review calling it "a fun but poorly paced horror adventure."
Check out our list of the best horror games to make sure you haven't missed any.