Not quite. If you see the original quote "now" is referring to the situation after ABK and how this allows them to be in a larger space, especially the mobile market. Because Xbox already launches games on other consoles and after ABK in even more quantities.
I don't think anyone is certain of what MS can do, but these words from Nadella definitely do not clarify anything for one side or the other beyond what is already a reality today. And that reality is that XBOX is already the main publisher on PlayStation and soon on Switch, in addition to launching games on PC and mobile phones...
That is, that is the place where they wanted to be of course. I perfectly understand the interpretations that each one can (or wants) to make given the ambiguity of MS and the "strange" situation of Xbox now that it has ABK + Bethesda and an extreme multitude of Studios that need to be amortized.... But it is It's a question of applying the logic and if MS (as confirmed) is going to continue releasing console hardware and establish an attractive ecosystem for potential users, it will certainly need exclusivity for that ecosystem. XBOX did not buy so many Studios, Bethesda and especially ABK to be a simple 3rd party like EA or Take two.....
This is where what many here denied or affirmed a lie from MS in the ABK acquisition thread comes in... "case by case". This has turned out to be true. How far will this "case by case" go? This is what we are going to see over the next few years.
The answer is pretty clear imo.
The Activision acquisition is signaled by Nadella as the turning point compared to what they have done so far that will allow their long time goal of being a major publisher releasing their games on all platforms.
If he was talking just about a few selected titles there would be nothing new compared to the past that they can only do *now* (post Activision acquisition), the answer would have not much sense.
The reason behind that is clear, you can't invest 80 billions on publishers that used to work also financially by being fully multiplatform just to try to drive sales of an almost dead console brand or only to push a subscription service that has already saturated and is unlikely to get the subscribers they need to offset the costs of putting all their games day one there.
More games they add, more difficult and complicated is to sustain the situation. Adding COD on Gamepass this year will create a revenues hole even with the game still available on Playstation.
Also not focusing on console platforms anymore has been their desire, their decision to kill console exclusives is the main culprit behind Xbox Series doing worse than Xbox One...and this is all on them, not even the competition.
So this is a logic conclusion, not a sudden development.
Of course there will be graduality, they will never say they're abandoning hardware, they'll never issue a PR stating they're going third party. We won't see games where they already paid for the exclusivity (ex. Indiana Jones) becoming multiplatform day one.
But we'll see more and more games going fully multiplatform. Multiplayer games and old catalogue games will be the beginning.