Pull it off? Easier said than done.
Take a look at Netflix.
Video streaming giant Netflix had a total net income of over 2.76 billion U.S. dollars in 2020, whilst
the company's annual revenue reached 25 billion U.S. dollars.
The number of Netflix's streaming subscribers worldwide has continued to grow in recent years, reaching 204 million in the fourth quarter of 2020.
That's 210 million subs right now (as of Q1 2021). Look at those numbers. They make 25 billion revenue for a whole year and the bottom line of Net profits, their earnings, is $2.76 billion.
Netflix is everywhere. It's not tied to some specific hardware, Game Pass you need an Xbox or a PC (and let's leave aside Xcloud for a moment, that's a big hypothetical future). Netflix is a service that all people can enjoy, it's movies and TV, gaming is not for everyone.
Netflix produces its own content, they also pay third parties, but they have become very efficient in making their own very diverse catalog in a matter of few years and continue doing so. Their content ranges from B to AA quality (mostly AA) and it's less expensive and time demanding than game development.
Long story short, a service like Game Pass is much more expensive to maintain than Netflix, it's also harder to market and gain subscribers because it's tied to specific hardware and smaller gamer demographic.
MS is currently investing millions developing unique content for the service hoping that will have a significant lasting impact on bringing more people over. But a game takes 2, 3 or more years to make, and most of them have a gaming life expectancy of 2 weeks max. People beat a game (if they like it enough for it) and move on, a Netflix Series season is made in less than 6 months, people watch it and in a year or less they will have more to watch of each one, so there's way more incentive to keep subscribing.
I could go on, but the bottom line is, Netflix is a pioneer and right now facing very strong competition. They spend a lot, they make 25 billion in revenue and "only" take 2.7 billion to the bank. That with 200 million subscribers.
You really think Game Pass has a chance at profitability, maintaining more demanding servers, paying pricier pieces of third party content, maintaining Xcloud, paying EA for EA Play, spending big on AA/AAA games that won't sell well because will be day1 on the service, and all the while their subscriber base growth is tied to the success of hardware sales (Xbox consoles or capable GPUs). As a whole the gaming industry sells 200 million consoles in a span of 7 years, add to that roughly 100 million PC gamers. Even if all of those 300 million would subscribe to Game Pass, it would probably still be a losing game.