The success of the states' lawsuit against the tobacco companies laid the ground work for this and wetted the appetites of the states' attorneys for big payouts.
This is no more than suing for dollars. Either the big corporations fold; making deals in which they pay but admit to no wrong doing or fight in court but risk huge judgements.
It would never occur to judges or juries that prices like water seek their own level.
The tobacco deals were not about alleged barriers to fair competition, but about alleged vice.
IIRC, some of the earliest antitrust action was in situations like Rockefeller’s Standard Oil company, in which agreements were made with product transportation companies to favor one brand of a fungible product over a different brand. It’s harder for water in a sealed reservoir to find its level with anything else.