Honestly, if you have Stadia Pro, you've done yourself a disservice if you haven't picked up Far Cry 5 (and New Dawn, to boot) already. And now if you're a Pro user, you can see what I'm talking about this weekend, with the game free to play through Monday. But for those who do give it a shot, there can be a lot to like, and for me, Stadia really became something I was excited about last fall with the release of Far Cry 5. The library is still maturing, there's always the fear of connection issues getting in the way of gameplay, and plenty of people are just going to be more comfortable going with a gaming solution from a company with more history in the field.
Stadia can be a tough sell for a lot of gamers.