The RIAA and MPAA are the driving force behind the copystrike behavior. I do think Alphabet has the resources and standing to resist and battle it in court, but that’s clearly not their business model. Alphabet is not invested in protecting content generators, only in what metrics they can sell to ad agencies.
Epic doesn’t care about any particular product or service. They are a publishers with aims to become a storefront, but plan to do so by passing off customers and devs and partners.