The proposal is quite practical and possible to implement for someone like Google. Some of Google employees said as much as to suggest this exact thing to Stadia execs. So I do view it as people not caring enough, if all they say is "it's ridiculous". All they'll get is the DRM in result.
That would help DRM supporters, sure. I suppose you are one too. What are you doing on GOG though, trolling in threads?

nah, I'm a not carer. neither support or not, but let people do as they want. DRM is not the be all or end all of things.

So how much entertainment value do facepalms go for these days? ;)

They're definitely cheaper these days. In the old days you had to buy a certain type of printed periodicals... or surround yourself with a certain type of people.

So the dev has to:
1. Code and maintain the game for Stadia.
2. Code, maintain, support the game for Linux and Windows (Sorry not enough users on Linux but could be if they streamed the game...) and provide Vulkan support for both and also not implement DRM as well as testing and supporting all the different combinations of hardware....which they don't have to do for Stadia.
This is assuming that the DRM free game is the same as the Stadia game which isn't likely since the benefits of these Cloud platforms are to take advantage of Cloud features like analytics, price gouging, larger worlds, higher end graphics (excepting for issues caused by the connection of course), etc. Singleplayer provides no benefit to publishers unless there is a way to monetize and if subscriptions are used you can be they'll need to find other ways of making money. $10 a month (guessing) for access to 1000+ games doesn't provide much to the publishers.

Scaling requires coding for that. More than likely with Stadia they'll be able to purchase certain amounts of computw power which will be guaranteed with an SLA. Why worry about scaling for their game if they don't have to? If they wanted to provide a DRM free version of their game they'd have to code for that from the very beginning or go back and modify their code to add that.

Elimination of mods prevents issues that the game companies no longer have to deal with. See Rockstar and Hot Coffee which was BS but that's what you get when gaming is no longer for gamers but for regular people. It's only going to get worse so best to nip it in the bud.

Google has to:
1. Code, support and maintain Stadia
2. Provide an interface and distribution for DRM free games as well as potentially watermark files for tracking. As well as provide a method for updating those games. If they are multiplayer then they'd also have to mandate "DRM Free" multiplayer otherwise they'll have to provide a multiplayer backend or the dev would.

You can't explain DRM free to people. The people these things are being marketed to have no concept. They just want something and they want it now without thinking about the consequences. That's why the world is as screwed up as it is. They just got off of working after wasting their time for 12hs in a job they don't care about and then have to take care of their kids for another 4hrs. They might have 5-30mins throughout the day or mabye an 1hr where they can play some mindless microtransaction, ad ridden, gambling addiction mobile game and they really don't care. For kids they are young so have plenty of time to play whatever the latest multiplayer game is and they and just want to play whatever their friends are playing. Mabye when they hit college or post college they might have some nostalgia but it's rare. The numbers are just not there. The best you can hope for is that the niche of people that care is large enough for what you want. I'm sure the bean counters at Google have already run the numbers and came up far short.