Burritos are particularly robust to delivery (along with Pizza, Chinese takeaway, and curries). Most finer meals, and even items such as sandwiches or hamburgers, aren't. I don't see a large market for duck a l'orange avec quadcopter however.
Even food deliveries, though, probably don't pass the sniff test.
For me, seeing some new fancy tech prototype or proposal that looks to be unsuited to general commercial or residential use, I tend to see a submarine military application. Drone distribution in a combat environment could conceivably make sense (though it would risk blowing cover in many cases). Emergency response, research, fieldwork, construction, and disaster response are a few other potential fits. Much less price sensitive, high time sensitivity.
But mass delivery of random consumer stuff in an urban or suburban environment? Not very likely.
I suspect the problem just sounds too cool and is sufficiently engineer-catnippy for anyone to say "no" in time.