Sure, but right now all of those takeout prices are from restaurants with retail locations. A ghost kitchen that offers delivery could be undercut by a ghost kitchen offering pickup, but in general they'll have a price advantage versus a retail restaurant with a more expensive location and more square footage.
The calculus is especially favorable toward ghost kitchens during pandemic-induced lockdowns, when people aren't otherwise out and about. If I'm driving home from work and can easily stop by a restaurant for takeout, that doesn't cost me much time. But if I'm at home 24/7, then I factor in the time spent going to get food. That makes ghost kitchens with delivery somewhat more attractive.
On one side being home 24/7 gives me a lot more time to cook myself, on the other side going out to buy food finally makes sense, it's one of the few occasions I have now to go out and have a walk in the open.
There is a different market for customers that are willing to pay the cost of delivery, they usually have more mouths to feed, and those mouths are pickier.
If anyone is ever brave enough to actually test this I think they would be surprised, especially during COVID.
Restaurant doesn't deliver? Provide an option to deliver for $20 and I am certain that you will get orders.