A complicating factor in all of this is the unfolding anti-trust cases against Google and other large digital platforms (see: https://www.nytimes.com/2018/02/20/magazine/the-case-against...). Choices that Google might have once made to improve search results for users are now under extra regulatory scrutiny. I imagine Google executives would be very careful about making any moves that could be cast as freezing out competition, even if that competition is abusing Google's platform.