Yes, for a bigger drone. Economically, probably not. 40 mph in a car covers a lot of 400 m sections in the course of an hour. Drones would be good to fill in a few spots to get adequate coverage of a few nearby blocks, but not for general data gathering. And not for tens of thousands of blocks.
This is a classic case of making required evidence nearly unobtainable, in order to prevent questioning of the current truth.