The US has such lax anti-competition laws and enforcement, even if it was I highly doubt they'd ever even consider Google (Or Apple) in an anti-trust position let alone enforce it. The EU has done a little more here, but everyone online queues up to criticize them every time they do anything to try and protect consumers, so c'est la vie.

The textbook anti-competition case, US v. Microsoft, was thrown out at the end of the day and settled. There is effectively no anti-competition oversight in the US.