Exactly, I had the same issue with this. If Google isn't some form of a monopoly with Chrome, their search engine and advertising... then literally nothing qualifies at that point.
If it's still not: Users must actively take the step of downloading and installing it. Is this step less difficult than changing the default search engine in Firefox or Safari?
And Google guide people to how to install chrome and majority of people can download some exe and run it with next next while keeping the defaults. And many of them will not change any of the settings. And chrome will take every chance to let you revert back to google search if you happen to change it.
The entire antitrust regime from it's inception, all of the caselaw, is a mixture of judicial activism, chest thumping, and executive branch blackmail. It should all be struct down. Start again.