I’m sure the author would be the first to agree that this isn’t a detailed analysis - they had various comments to that effect - but it doesn’t change the point by anywhere near enough to invalidate it. Most roads are not long dead end streets and especially now that people use navigation apps there’s a lot more traffic on neighborhood roads than there used to be, too.

The big problems are low density and how much most cities end up subsidizing non-taxpayers who drive a significant fraction of road demand with only minimal economic contribution. Those subsidies are doubly expensive because they hurt the city and discourage use of more sustainable transportation.