The judge in their case decided that the relevant market was mobile gaming, not app stores or in-app payment processing, and since technically Apple didn't have a monopoly there, the whole monopoly claim by Epic was deemed invalid by that judge. Courts can be stupidly black & white sometimes but that's how it is and a whole case can be tossed out based on a technicality. Google v Epic however was a jury trial and Epic obviously took lessons from their loss against Apple.