Microsoft seems to know that, and so far hasn't committed to any notions of exclusivity, merely saying that they would take it by a game-by-game basis. That said, in a talk at the Jefferies Interactive Entertainment conference, Xbox chief financial officer Tim Stuart actually shared more specific information about Microsoft's plans with Bethesda going forward.
Namely, that while Microsoft has no intention of depriving Nintendo or Sony of content, they still want to have a competitive edge over them.
"We highly encourage cross-platform play, simply from this landscape of, if it's good for the gaming ecosystem, it's good for us, classic rising tide lifts all boats... what we want is we want that content, in the long run, to be either first or better or best or pick your differentiated experience, on our platforms. We will want Bethesda content to show up the best as—on our platforms... If you think about something like Game Pass, if it shows up best in Game Pass, that's what we want to see, and we want to drive our Game Pass subscriber base through that Bethesda pipeline."
Their job is mostly done for them, to be honest. Bethesda games, specifically the ones they're known for, like Fallout and Skyrim, have always thrived largely on the backs of the modding community, which is a PC -- and thus, Microsoft -- focused-venture. But to extend that to Bethesda's other, less mod-reliant offerings still sounds like a smart yet fair way of moving forward.
I wouldn't hold my breath on Nintendo adopting that strategy anytime soon, though.