I wouldn't be the one to ask about the details, but I think it would be foolish to surmise that two companies taking up 3/4ths of a sector shouldn't go through some anti-trust scrutiny.

77% of the U.S. 3rd party food delivery is DoorDash + Instacart.

(Nearly all of the remaining amount is Uber Eats.)

So if not a monopoly, then at least a duopoly.

As a rule, two-sided marketplaces are very difficult to disrupt.