I have absolutely no confidence that they'll get there without it.
They already have Zenimax and we haven't much to show for it. It was releasing more games before it was acquired. But I'll grant that not enough time has passed, though I'd say if Redfall wasn't up to shape they could and should have changed the release plans.
But for Rare plenty of time has passed. What do they have to show for it? Sea of Thieves and a Killer Instinct game for the whole of the last decade. Banjo has been declared dead, Perfect Dark keeps getting postponed, and nothing else new. It doesn't bode well.
We just saw a ton of games that they're making.
It wasn't all that many, and most of it likely came at expense of what would previously be multiplatform games. Zenimax would still be releasing games if they hadn't been acquired. Sure, exclusives benefit them but this "competition" was really a net loss for players who don't have Microsoft platforms. It came at expense of the third-party market.
There is no functional difference between this and buying other studios, especially since Naughty Dog was also a studio acquisition.
There is a marked difference in scale. If they just bought Treyarch or Toys For Bob that wouldn't be a big deal. But they are bulk buying publishers along with all their studio subsidiaries. Activision Blizzard by itself is the 6th largest publisher. This is not just getting a studio. The comparisons being made to excuse Microsoft's tactics are really glossing over what a drastic sweeping takeover they are doing, All the while they whine about how tiny and feeble they are, because this massive company doesn't dominate the gaming market also.