Microsoft's head of publishing said 7 years ago now that she didn't know if single player games were viable business anymore due to the increased costs of meeting player expectations re: graphical and technical fidelity. I remember that it was 7 years ago because she said it in 2017, a year where the PS4 had several well received single player games. The question is: would the bean counters at MS actually consider games like Nier Automata, Persona 5, or Nioh to be "financially viable," even if they made money? Those games were considered successful for selling a couple million copies, but I don't think that's what the business division of Microsoft expects.
On the other hand, I imagine it's difficult to make huge profits on GaaS titles when your platform is behind the others in terms of install base. For all the dumb shit Spencer has said over the past handful of years he at least had some prescient quotes about how Xbox ultimately messed things up at the worst possible time. The beginning of the PS4/XB1 era was the beginning of people committing to an ecosystem of digital games and online accounts. Even if they weren't out there doing silly shit like passing on Hoyoverse rights they still likely wouldn't have the market on their platform to capitalize on those games because those people all chose Sony's ecosystem in 2013 and the years that followed.
I think single player exclusives have always been used to drive people to your platform. The only company who makes that their bread and butter is Nintendo, who are also the only company to consistently turn a profit on hardware.
I think for someone like Sony with their massive projects it's about making a slight profit on the game sales themselves to somewhat balance out the hardware R&D and production costs, but they are primarily used to drive people to the console where you make 30% off 3rd party sales and MTX.
I think the real question with MS's is, on top of being a distant 3rd in hardware sales, what has gamepass done to their 3rd party sales they make 30% on but have no development costs on. That historically has been where console manufactures see their profits arise from. The other thing is, with first party you are making 100% of sales (or around 95% to 90% on physical copies) even if it's not on all platforms, which also helps offset development costs compared to the 70% 3rd parties make. MS's has pursued all digital much more aggressively than Sony and Nintendo with Hellblade 2 for example being digital only.
It would be really interesting to see someone much smarter than I get an actual look at Xbox's numbers, but MS has been very secretive of them since around the Xbox one launch.