For me, the fact that Google has >50% market share on Edge is proof that Google is right. Consumers clearly know how to change defaults when they want to.
A large combination of dark patterns have contributed to Chrome's market share. (to name just one: Installing Flash for Firefox or Internet Explorer? Get Chrome installed at the same time (which, guess what, doesn't even need the Flash plugin you just installed, because it embeds its own))
Defaults definitely matter (that's why Google pays Apple for default status), but legally what matters is if the contracts are exclusive. That's what this fight over the "power of defaults" is about. Microsoft and the government argue that they are exclusive because, while consumers can change the default, they don't in practice.
But the fact that consumers clearly know how to change the default on Edge fatally undercuts that argument. And if the contracts with Apple aren't exclusive, Google can't be liable for them under the antitrust laws.
I forgot the scope were so limited in the US. Going back to the Microsoft trials vs the EU, there was no exclusivity limitation, users could use other browser, or install other OSes, the point was solely on what pressure MS put to be the first choice.