I feel like the same reason they would make a good fit (third person single player) for Sony is the same reason Sony shouldn't buy them. I feel like Sony could use a bit more diversity in their portfolio. Horizon, Uncharted, Detroit, God of War, Days Gone, Bloodborne, The Last of Us. All great games. But would it kill them to do something a little different. Like these are the heavy hitters. Could we spice it up a bit. I'm afraid Remedy would become another Bend or Sucker Punch style studio. Or worse become like Ready at Dawn that made a big budget flop and is no longer taking those kinds of risks.
Where I could see Remedy fitting in well is with Take 2 or maybe even under the Bethesda umbrella. I could even see them partnering up with Microsoft. However, I agree with you that it would be a harder sell. Mostly because Alan Wake and Quantum Break didn't exactly set the world on fire.
Well, Ready at Dawn isn't a first party studio. Even Remedy after AW and QB can't take big risks, Control had a budget nowhere near big AAA productions and its publisher isn't one of the big players.
A new AAA project from Remedy could only come after a acquisition from a big company that wants to invest a lot of money in a single player story driven experience. I do not know a lot of company that invest in that direction anymore. Maybe Bethesda even if right now I'm a bit worried about their future heading into next gen. EA if Jedi Fallen Order is successful could start a new interest in single player, but it's still EA, they have to work hard to gain more faith from me, lol.
Microsoft, as I said earlier, is a good match (former publisher, IPs, possible interest in diversifying their portfolio of games for game pass, ecc...). However, like you said, their precedent collaboration wasn't so successful and I think that an acquisition for gamepass would lead to a smaller, quickly developed, less expensive games. I really see a game like Control perfect for a subscription model (interesting cool original concept, conscious budget, small development time), rather than a big budget AAA game that takes 3 or 4 years to make.