Okay but how long will it take for them to reach 100 million GP subscribers, more-or-less concurrently? It has taken 5 years to reach 25 million, with very little competition from alternative services. At that pace it will take 20 years if level of competition from alternative services remains the same...but that won't be the case. Not only alternative services, but just alternative avenues for gaming in general (including rival consoles, games, storefronts etc.) will continue to increase.
That will probably slow down the rate Microsoft can reach 100 million GP subs, possibly greatly so. Are Microsoft really going to wait that long to break 100 million, or will they reach those gamers through other means, like utilizing the reach of their acquisitions to get gamers on mobile (King), PC (Blizzard, WoW), and other consoles (Activision, COD/Crash/Spyro/Tony Hawk/Guitar Hero etc.)?
The latter seems more likely for me, and that isn't really dependent on big GamePass growth let alone big Xbox console sales. But I guess we'll see.