In my opinion the concept of cloud gaming is cool and could potentially become big if done right for several reasons:
-No downloads or updates(one of the biggest complaints this recent gen)
-Seamlessly jump into a game from any internet connected device
-Have the same console experience from anywhere with no graphical compromises
-Not needing to purchase expensive hardware
However, as someone who tried a Free Month of Stadia there's just really isn't anything attractive enough about the service to warrant playing your games on it or paying 10$ a month.
I tried playing Destiny 2 on my laptop & smartphone with Stadia. It was so laggy and unplayable on my laptop, but on my smartphone it actually ran quite smoothly for the most part & was more than playable and I'm not gonna lie seeing something as big & visually intensive as Destiny 2 on a smartphone was pretty amazing.
However I'm still reluctant to use Stadia for several reasons. For one thing is that while you could technically get Stadia for free now, you realize that there are far more hidden costs that just don't make it worth getting or using as your main platform. First to play your games in a competent way you're gonna need a controller, where a Stadia controller costs 70$, you could use other controller options like Xbox or PS controllers for Stadia or a mouse & keypad, but chances are if you have a PS/Xbox controller, you have a PS4/Xbox, consoles that have far more games with far better game deals with way more free games than Stadia, making Stadia essentially useless if you're a PS4/Xbox owner, which is the VAST MAJORITY of people in 2020 with combined sales of 160M. However, let's say a casual gamer who doesn't own a PS4/Xbox or PC & wants to get into gaming affordably, they're gonna need to pay 70$ for a Stadia controller, and if they want to play on the TV they're gonna need to pay another 35$ for a Chromecast Ultra, adding to 105$. 105$ is still cheaper compared to Xbox & PS, however Stadia games at this point tend to be far more expensive than the other consoles so eventually the costs will add up to the price of a PS4. Plus even just a 70$ controller for this Stadia service isn't even worth it at this point, you're paying 100$+ to play on a platform with an extremely small community that barely has any games and exclusive content that isn't even guaranteed to work depending on your internet connection. Imagine if Sony released a PS5 where a good portion of them don't even work properly, that's essentially Stadia rn. Plus some Stadia's main "advantages" such as little loading times will be completely void once next gen systems release with SSD's that'll almost eliminate long loading times all together. I wouldn't recommend getting this service either cause Google is known to drop their some of their products & services like hot turds when they see it's failing, like Google+, and all your games will disappear since you won't own them & developers could at anytime remove their games from Stadia like what they've been doing with NVIDIA Ge-force now.
Could Stadia comeback? IMO I honestly have little faith it could, I feel like XCloud will murder Stadia in whatever it has to offer and has far more value and Xbox has a more trustworthy name than Stadia, I don't see the mass market wanting to choose Stadia over PS/Xbox in the future. But if Stadia wants to comeback, it's obviously gonna need t completely iron out all lag issues some people may have, get FULL 3rd Party Support, get more exclusive content, & have a more competitive price point for consumers to be willing to try it out.