Monday’s court ruling that Google created an antitrust market with its app store threatens to upend the $500-billion-a-year app store economy, which has evolved into a profit machine for Apple and Google that helped define the smartphone era.

A jury unanimously sided with Epic Games, saying that Google had harmed the videogame maker by maintaining an illegal monopoly. Google said it plans to appeal the verdict and stands by its business model. In a separate case that concluded in 2021, a federal judge largely ruled against Epic even as she ruled that Apple must allow third-party software makers to steer customers to payment options within their own apps. The outcome might ultimately be decided by the Supreme Court.