Seeking Alpha:

The incentives for this are clear: a reduction of the App Store fee from 30% to 15% or even to 0% would make all of these would-be accusers immensely more profitable. In the case of Tile, Epic and Spotify’s victory would give legal precedent to pile on to the misleading claim that Apple engages in anti-competitive and monopolistic behavior.

And on the punishment of a monopoly:

The Sherman Act imposes criminal penalties of up to $100 million for a corporation and $1 million for an individual, along with up to 10 years in prison. Under federal law, the maximum fine may be increased to twice the amount the conspirators gained from the illegal acts or twice the money lost by the victims of the crime, if either of those amounts is over $100 million.

And:

Apple is not a monopoly. It does not produce necessity goods and it does not force consumers to use its products or the App Store. It does not force developers or competitors to use its products either – Fortnite or Spotify’s offerings do not constitute necessity goods and can be purchased elsewhere – not only through Apple’s App Store. At the end of the day, any company that chooses to sell its products through the App Store has a choice, as does the consumer.

There’s a lot more to this read. Hard to say whether this conclusion is valid, but it is an interesting take.

Also worth a look, the Sherman Antitrust Act Wikipedia page, a deep, deep rabbit hole of information.