Before there was Big Tech, there was "adversarial interoperability": when someone decides to compete with a dominant company by creating a product or service that "interoperates" (works with) its offerings. In tech, "network effects" can be a powerful force to maintain market dominance: if everyone is using Facebook, then your Facebook replacement doesn't just have to be better than Facebook, it has to be so much better than Facebook that it's worth using, even though all the people you want to talk to are still on Facebook.