Listen. Steam is free. Uplay is free. Epic is free. EA App is free. It's not like Playstation vs Xbox, where the market is divided because of financial limitations on the consumers. What stops anyone from using any other launcher? What stops any publisher from not selling through Steam? "market share" is not really a valid argument when all options are free and easily available to everyone. Monopoly means lack of alternatives.
Right now the option is buying a game for $70 on either Steam or EA App, for example. People choose Steam.
Nothing is stopping EA from saying you know what, we'll sell it only on our own page but for $60. Nothing. People who want to play a game would most likely just buy it there then.
My view is that these lawsuits etc are purely a way for the failed competitors to force their way in while still providing the same absolute garbage of a service.