>> through market competition not through impairing the ability of smaller companies to enter markets.

So? In the real world, antitrust isn't about how a company became dominant. The fact that a company is dominant is what matters. Legislatures know that having a market run by one entity is inevitably a bad thing. Google's success, its market dominance, is the very harm that antitrust is meant to address. How Google got there isn't relevant.

If the government deems an organization too big, there is always something on which to hang the prosecution hat. Price fixing, tying, vertical restraint, dumping... they will find something.