Until all the titles that are under contract are out, then it'll be exclusive to Xbox/PC.
Its just not that simple.
Until the addressable market from their platforms and services can exceed what was formerly attainable with multi-platform publishing its the definition of leaving money on the table because what it boils down to is abandoning a proven, highly lucrative revenue stream.
Will going exclusive drive more users into the ecosystem? Sure, but you aren't going to get 100% conversion even assuming that you have capacity to support that extra number of customers - something that isn't assured by any means.
There are a whole load of other considerations both pro and con, but the loss of revenue on an annualized multi-plat franchise thst runs as a live service is especially impactful.
The objective is to make money and become dominant, not to win every battle on every front even when doing so inflicts damages on your bottom line. That'd be stupid.
No company ever "moneyhats" everything. Because its just not necessary.
More than that, if the only way you can "win" is by locking down everything, what does that say about confidence in your brand and reputation?