I don't think they are short-sighted. I think they realise that the app store gives them such a leg up in the process of packaging, distributing, managing updat

I don't think they are short-sighted. I think they realise that the app store gives them such a leg up in the process of packaging, distributing, managing updates, helping with discoverability, ensuring platform compatibility and (optionally) taking payment of their software that they easily see the value advantage to going on the app store other than doing all that themselves. Managing all of that yourself would leave less time for development, would cost a lot more than the app store fees & cut and would be in itself an insurmountable barrier to many who might not even bother (particularly small freeware apps). On the whole I'd say the app store benefits the majority of developers, particularly smaller ones. The companies that do chafe at the bit though are the larger ones for whom all of that infrastructure is already taken care of, and it's no barrier for them. They seem to resent Apple's cut which would probably explain the Fortnite fracas.