I think the idea is that they want to shift the focus off their legacy products - consumer software, ads - and move on to random bs like robots, medicine, and social experiments. Investors don't necessarily want to do that, and they also need to preserve their valuable classic Google business, so they're separating. Its scary to think that they have enough capital to do such a thing and see enough opportunity... to set their goal to longer be competing with apple in phones, microsoft in software, and facebook in ads, and put all that on the backburner. I think in their new field they own the whole thing and there's no real competition, and this way they'll keep it like that when the market pivots all together.
