Do you have an economic or legal reference for that definition of "monopoly"?
Since search engines are all free to use, many of the criteria of a monopoly seem hard to apply, but the classic defintions I'm familiar with include things such as "no reasonable substitute" which is not the case for Google Search.
Re:AMP for email is a terrible idea
by icebraining on Wednesday February 14, 2018 @11:15AM
(#16376865)
Courts do not require a literal monopoly before applying rules for single firm conduct; that term is used as shorthand for a firm with significant and durable market power — that is, the long term ability to raise price or exclude competitors. That is how that term is used here: a "monopolist" is a firm with significant and durable market power.
https://www.ftc.gov/tips-advice/competition-guidance/guide-a...
Just so everyone's clear, monopoly doesn't mean (nearly) 100% market share; it means a large enough market share to be able to manipulate the market.
So, to elaborate on your first point, I think you're saying that the ease of switching search engines means that a market share necessary to manipulate the search market would be near 100%, much higher than Google has. Am I reading you correctly?