Yeah, I know this sounds stupid, but I mean, the majority of games are there now.
The signal is all that's needed, I work in AAA games and we shifted heaven and earth to make Stadia work. Which means somewhere in Ubisoft there is a fully functioning version of Watch Dogs Legion and The Division that run natively on Linux.
And the answer was the same when I asked why we didn't release it: we don't see a market, and we don't want to maintain another channel of support.
Right now it's not costing them any meaningful sales, so why would they put the investment in?