That Google is able to employ such tactics with the implicit understanding that its customers will not abandon it for a competitor argues that it has coercive monopoly power
It's implying no such thing. The actions of a company can not be linked to coercive power without understand the needs or wants of the customer first. There is some benefit to both parties that Google's results are promoted to the top and many customers like getting consistent and understandable results. I.e. if I type "maps" into Google I would see it as a sign of a failing search algorithm to not promote Google Maps to the very top of the list. It is incredibly interesting that Bing will also list Google as the top result for maps, and only lists itself as number 4.
Coerciveness and lack of effective competition is orthogonal to both relative ability to competitors and benefit to consumers. Government entities including courts have sometimes made decisions based on the impact to consumers, but the coercive nature of a business and its ability to unilaterally impose its will on the market can still remain.