Anti-trust law really has broad authority if they can make this stick. Just because this is tech doesn't make it special. The EU fines were nothing. If this goes well, it would be a forced dismantling similar to what happened in the early 1900s. Google would have to win the case or cease having any U.S. presence whatsoever to get away from this.
I think it is a little too late now. Companies like Google have grown to the size where it is now impossible to stop them from being a monopoly.
I don't think there is anything, anyone in the world can do to really allow a fair competition in the space.
As for the fines that e.g EU has inflicted to Google in recent years, they are simply ridiculous, considering Google's revenues.