If they were that good, why would Google have to waste money pre-installing them as defaults?
Because most people can't even change the search engine even if they wanted to. Whatever Google is the best search engine or not, pre-installing is a different problem.
To keep somebody else from doing that. Now they don't have to because nobody can.
That really misses the point. That is, fines do nothing if they are a rounding error on revenue.