Earlier quoted context omitted.
Of course, those regulations to support dense housing need to be supported by other things; like money for streets, sewer, water, etc. If the town's streets are already crowded with traffic and it's sewer system can barely keep up, then building dense housing it going to destroy the town. And for a town that is already "in place", adding a bigger sewer system is hard. Widening streets is even more difficult because y…
You've got it exactly backwards. Density is cheaper and more sustainable than running miles and miles of brand new sewerage, roads etc into spread-out suburbs. The big difference between Japanese and American cities is that Japan is built for trains, which scale up really well, and the US is built for cars, which don't.
I'm not talking about constructing a town from scratch. I'm talking about an existing town. Adding the infrastructure for high density housing to a town that wasn't originally designed for it is very expensive.