So you do understand food delivery. Is it a stretch then to imagine why a service that expands the delivery market from a handful of pizza and chinese restaurants to ~every restaurant in the city (that wants to opt in without hiring its own fleet of drivers) is successful?
Yes. The quality of a delivered pizza is higher than the quality of other delivered foods relative to the quality of getting them for dine in at the restaurant.
I live in NYC and 9 out of 10 meals I have delivered are hot, fresh and show up on a bicycle in about 25 minutes. I know that not the norm, but a good 20-30 million Americans live in areas with an astounding number of fast and diverse delivery options and it should confuse no one as to why people take great advantage of it.
And those same urban-dwellers are far less likely to own a car, and far more likely to have a tiny kitchen.