I'm surprised a guy in finance can't see the potential efficiency gains and economies of scale a delivery company could have over all restaurants having to oper

I'm surprised a guy in finance can't see the potential efficiency gains and economies of scale a delivery company could have over all restaurants having to operate their own delivery service. I don't know about DoorDash specifically (not in the US) but it seems obvious to me that those services are here to stay and they can be run profitably.