The only thing a copycat needs is that manufacturers be allowed to install it as the default app store, without ruining their relation with Google.
Once that happens, copy cats will pay manufacturers to preinstall, leading to customers, leading to developers who want to tap that still uncrowded market. And once multiple app stores bootstrap, a price war is inevitable - margins of 30% would be undefendable since they would be passed on to the consumer who would switch to a cheaper app store.
It's very clear why Google would want to prevent such a race.
Once that happens, copy cats will pay manufacturers to preinstall, leading to customers, leading to developers who want to tap that still uncrowded market. And once multiple app stores bootstrap, a price war is inevitable - margins of 30% would be undefendable since they would be passed on to the consumer who would switch to a cheaper app store.
It's very clear why Google would want to prevent such a race.