The below took me about a minute to find through Google.
U.S. v Socony-Vacuum Oil Co., 310 U.S 150 (1940); United States v. Sealy, Inc., 388 U.S. 350 (1967); United States v. Topco Associates, Inc., 405 U.S. 596 (1972); Craftsmen Limousine, Inc. v. Ford Motor Co., 363 F.3d 761 (8th Cir. 2004), Northern Pac. Ry. Co. v. US 356 US (1940); Agnew v. National Collegiate Athletic Ass’n, 683 F.3d 328 (7th Circ. 2012); or In re Flat Glass Antitrust Litigation 385 F.3d 350 (3rd Cir. 2004), National Soc. of Professional Engineers v. U.S. 435 U.S. (1878); In re Insurance Brokerage Antitrust Litigation, 618 F 3d 300 (2010); or In re Southeastern Milk Antitrust Litigation, 739 F.3d 262 (2014).
Your argument, if you can call it that, is completely incoherent.
You seem to be under the impression that anti-trust is isolated to monopolies, when clearly it is not. Apple and Google do not need to have a monopoly for the government to decide that their app store business model is anti-competitive, and there doesn't need to be precedence.