you are providing good responses and valid points more than most people ... the answer is the same in reverse
they are doing it because it makes money dog
I said for almost a decade just upgrade your computer and people wont.... so here we are in 2020 ...with people just now buying 540$ systems and tricking off money because they can. We are on the same line of thinking, what we both could say is... with equipment costing this much why not just buy a PC? The convo gets weird here because it branches off into whichever point someone wants to prove to feel right. With Nintendo, Playstation, Stadia etc ... you think the biggest company out of the bunch isnt going to throw some shyt together to purchase? They easily made 10's of millions of dollars today...why would they move away from that? If I can ride Chevy Cruze, that doesnt mean I still dont want the Corvette. Chevy is happy to provide both of them. This is literally what they do.... like you said about microsoft being a percentage of PC in actuality, that's the entire point of why it was so easy to implement. They didnt have to build something that already existed on a platform they already control globally. They just had to network the Xbox, create an app and implement the gamepass straight to PC. The average gamer already pays microsoft the cost of the hardware back within a year of purchase or any system for that matter. You can look at anything in your crib to answer your question...
because there's a market for it.