I don't believe it's rejecting the monopoly concept, but rather pointing out that monopolies are but one (economic) instance of a broader pattern, monocultures. Monocultures are hyper-enriched in some aspects but depleted in many others and most importantly depleted in diversity. From game theory we can understand monocultures as an extrema on the exploration-exploitation tradeoff (trading off all exploration for exploitation). From evolution we know how this ends (poorly).

Monopoly law isn't about being the biggest provider.

Monopoly law is about leveraging your position as a big provider against competition.

Microsoft had as much market share in consumer OS. They didn't get in trouble for that. They got in trouble for killing Netscape by bundling IE and forcing Windows on all devices by charging per device sold regardless of whether Windows was installed or not. (Might have missed other suits but these are examples)

Government intervention to ensure competition rarely happens so maybe a new term to describe that would be good.