But having competitors/alternatives does typically help to bring the price down and improve the customer experience. Another store may take only a 5% cut, so apps can be offered cheaper.

You can argue that for subscription based services of IP content like netflix this doesn't really apply since you'll now need multiple subscriptions. But a big reason these subscriptions have to keep their prices low is because of the free competitor called pirate bay. If it wasn't for the alternative of pirating, we might not ever have gotten Netflix.