It's kind of a chicken and egg issue. Apple wanted users to stay in their ecosystem because they control it so tightly, which can increase the general security/trustworthiness of the ecosystem, but it also keeps those users for Apple's benefit. It's as though it's Apple's goldmine, which has restricted access, so the guy trying to bring in TNT to blast everything open isn't allowed in for both the safety of the authorized people in the goldmine AND the protection of the revenue stream in general.