Okay, fair, design costs have to be amortized across the userbase, and probably the correct solution to this is to build hardware people want to use with or without Stadia, so your design isn't anchored down. I.e. I can (and do) pair PS5 and Switch Pro controllers with other OS's. Obviously those other platforms don't offer the force feedback or HD rumble, but at the very least it's a signal to the your designers and the market that you expect your designs to be competitive in the open PC market.

Obviously less viable for the set-top boxes, but still a valid strategy if you can do it.