100 million equates to 1 billion dollar a month of revenue from just basic Gamepass. This equates to 3 billion dollar of revenue in the quater. This will be huge.
I speculate that Gamepass will reach 30 million by the end of 2021.
After that, if Gamepass is really the best deal in gaming, then it will blow up like a ballon and may cross 100 or even 150 million subs by the end of 2024.
All things are set on upcoming first party games starting from 2022.