Do they control the Trademark "Google"? Do they control the Domain Name "Google.com"?

Do they control the default Search engine for Android? For Chrome?

Did they pay to be the default Search engine on iPhone? On Firefox?

Are those rare resources? I'd say yes.

And you're conflating "illegally-maintained Monopoly" with "Monopoly." Whether they got there through using illegal tactics or not is a separate question from whether they are a Monopoly now. 90% - is that a high enough market share to qualify as a monopoly, when their annual revenue is like $224 billion? What percentage would be enough to convince you? Does it need to be 100%?