Curious why you think it is inevitable? The convenience of having the whole city available for delivery for consumers, and for restaurants to have access to a broad base of on-demand drivers and these customers, seems like an intractable modern day invention.
The issue isn't the delivery, we've always had local food delivery and it's a subsidised bundled service to sell the main product. The issue is whether they can run a tech company off the margins of delivery, where they take the risk setting the physical infrastructure to do delivery, but have little to no control over the actual restaurants providing the products.
