Google realized if they don't control the search distribution they gonna lose out sooner or later; which is kinda contradictory for them if they claim Google is the best search out there and that they are constantly improving it and that's why(they say), people choose it over other alternatives. But tbh distribution of your product/s is crucial.

Just look at Microsoft and their internet strategy, they chose the other route; push their internet browser(IE) down their massive distribution pipe called Windows and then introducing their search engine to this massive userbase. Fortunately this didn't work out for them but unfortunately that worked out for Google. And now Google essentially controls the Web in the more than half of the world.