It's not the first attempt at streaming. The others failed ...
Let's assume for a moment that the claims that Fdev were thinking of the next gen consoles in 2020 are true. Those are still going ahead, despite this announcement from google. If - if - Fdev wanted to convert their games (plural) from cobra to work with google's system, it would be an additional step to gain potential additional customers outside of the existing pc/microsoft/sony customer base. It won't be developed now for googles system, but converted later once complete. Post 2020.
In summary, meh.
I'm sure most third-party developers will be planning ahead to get their content on as many future platforms as possible. That just good business. Stadia is due for launch this year so I'm imagine some developers (and game engine developers) have been working on Stadia for a while. I'd be surprised if Frontier aren't already thinking about getting their content on there to reach a wider audience.
And if ED on Stadia means more players, more money being made by the game for Frontier and therefore expamding the lifetime of the game, then I don't see an issue with that.
Yes, other streaming attempts failed, but I doubt if any of those previous companies were as big as Google, or if they had YouTube and the world's most popular search engine to help them sell and advertise games directly to potential players.
Imagine doing a search on Google for ED and seeing a 'Play ED right
NOW on Stadia!' message at the top of the search results. You could do it too. No need to purchase hardware, no need to download the game. Just click, and boom, you're in. Whipping Asp Scouts for fun in a 10.7 TF instance.