I'm confused. How can you tie "increased sales" to having put them on Game Pass day one?
What would they have sold without being put on Game Pass, and who has access to those numbers?
Do they exist in 2 timelines?
OK, so, there are both employees at companies and entire companies whose job it is to analyze trends and predict the success and potential sale of products.
In general, these people and companies are very good at what they do and with games can easily get within 100k sales on smaller titles and 500k on huge sellers.
These people at both Microsoft and NPD had estimates for games like SoT, SoD2, FH4, and some smaller titles from 3rd parties like Graveyard Keeper. They have historically been pretty close to actual sales to the point that if 3+ titles all greatly exceed estimates, it is most likely not that they screwed up 3+ times, but that an external influence has affected the potential sales in a way that they did not account for.
The only uniform external influence here is GamePass. All were day 1 on GamePass and all exceeded sales expectations substantially. Well outside the expected margin of error for the estimates.
You and many others here may not be able to comprehend how these people do their jobs, but you should be able to recognize that companies pay these people hundreds of thousands of dollars per year for their expertise. It's clear they provide value and know what they are doing. Yet, because of GamePass they were wrong in their estimates and are now having to figure out how to increase estimates to account for the GamePass influence.
Part of doing so is determining what aspects of GamePass is actually driving he sales increase. This could be things like Twitch and YouTube, friends lists, posts on Social Media, or in person word of mouth. Most likely a combination.
Then they will try to determine if there are ways to get these benefits without GamePass or if something like GamePass is actually almost a perfect storm of features and functionality for this type of sales growth.