Earlier quoted context omitted.
"massive ad campaigns" is hardly an antitrust matter. Chrome ate Firefox and IE back in the day because it was monumentally better, technologically speaking.
Chrome when it released was faster than Firefox, but it wasn't "better". It ate far more RAM than either Firefox or IE did (and still does), back when RAM capacities were still practically limited, and Chrome was (and is) rendering the internet in Chrome ways much like IE did in Trident ways and Firefox has in Gecko ways. Chrome also had and still has its own UI paradigms, including no title bar, menu bar, nor status…
The Edge incident was kind of a perfect illustration of how Google either didn't care or actively threw spikes in rivals' wheels.