1. Netflix is actually over 12 billion in debt to pay for that expensive exclusive content. They are currently losing subscribers and stock prices are declining.
And that debt will get higher and that's fine, Netflix has been trending in the right direction for a few years now. It's just how they do business. IIRC Disney is also in a lot of debt.
You can buy all of these games outside of the service. It's not as if GamePass is the only way to experience them. Most Xbox owners and PC users still don't use the service. A monthly service fee and enticing users to buy DLC and the games themselves on sale can also recoup much of what you'd otherwise lose thanks to the used game market. MS is also not Netflix and not in any debt.
Your concerns are not unique but I just don't understand them. For these fears to come true MS would need to start limiting their software to GamePass or, at best, delay the release outside of GamePass for like a year after it hits the service. Then they'll have to find a way to get people to stay subscribed to the service while they apparently release small scale filler because they are cutting all the budgets. Also you mention Netflix and debt and admit they are paying for expensive content... why isn't Netflix cheaping out? Because they know that no one will want to buy cheap content. There is Hulu for that.