"Google owns or controls search distribution channels accounting for about 80% of search queries in the U.S., the officials said. That means Google’s competitors can’t get a meaningful number of search queries and build a scale needed to compete"

This doesn't seem right, technically speaking. I see estimates that globally they process 2 trillion searches per year (70,000 per second). 20% of that, 14,000 searches per second, seems a meaningful number of searches to scale to.

"The government will allege that Google uses billions of dollars collected from advertisements on its platform to pay mobile-phone manufacturers, carriers and browsers, like Apple Inc.’s Safari, to maintain Google as their preset, default search engine."

If the claim is that they are forcing people to use Google Search, reducing that 80% is going to require getting people to choose something else. The way that reducing the market share that is supposed to come from defaults has happened in the past is by forcing users choose which product to use instead. However, I posit that in this case a lot of the 20% comes from situations where there is a non-Google default. For example, one common request from people who notice is how to get Windows/Cortana to use Google instead of Bing. https://www.howtogeek.com/226638/make-the-windows-10-start-m...

I would do some user research about what people want to use before assuming that a massive lawsuit with a remedy intended to give them a choice doesn't result in the same situation. My (small scale) research indicates that more than 80% of people want to use Google.