Being the CEO's pet AI lab is one of the best positions to be in, as it's actually the rare combination of being able to do innovative work but getting all the resources of big tech to do it. Satya is no muppet; he knows that if he were to absorb them he'd have to keep anyone from messing with them. They would be the most protected class of employee at MSFT.

The main reason why you'd not want to do it is that Startup Funny Money stock options won't be as high as they might be if you'd stay independent.

Even in normal times, Microsoft does stack ranking. It's not great.