Wut?!
Both the comments here and previous comments from MS have been pretty clear. Combine that with common sense which says that no-one spends $7.5b (over-valued) on a multi-platform company only to strip away most of that value by not shipping games on one of the world's most popular platforms, while at the same time putting the entire publisher's games up for "free" on a pre-existing GamePass service (yes doing so will increase GP revenues through subs growth, but not by $7.5b, nor even by the amount needed to cover the depreciation in Zenimax's normal multiplatform sales revenues).
It's ostensibly clear that on the balance of probabilities, Zenimax games will continue to be multiplatform. Otherwise, Zenimax would see mass layoffs on the publisher side and the production operations would be subsumed into MGS with some small element of Zenimax's studio management team retained (because lord knows MGS studio management would make a pigs ear of it).
So trying to equate the two possibilities of future Zenimax games launching on non-Xbox platforms or not as equally probable is woefully disingenuous or just a little ignorant.
Just because there's no concrete confirmation either way, it doesn't mean both possibilities are equally probable. They're not.... and in this case, not even close.