Consumption goes up when things are more spaced out. Electricity needs to travel farther on lossy lines. Water needs to be pumped over longer distances. Deliveries need to be sent to farther and farther points. Heating needs to cover a wider surface area. Unfortunately all of these relationship grow as a power law of density so your consumption must increase by a substantial amount with a more and more spacious development plan. A quick look at the CO2 emissions per capita of high standard of living countries quickly shows that expansive countries like Canada, Australia or the United States have much higher energy consumption than dense ones like the United Kingdom, Sweden or Japan.

Because the land use is that much more productive. High density cities pay for suburbs which are a net-drain on city finances and are terrible for the environment. The numbers in North America are pretty staggering.

There are plenty of examples around the world where dense urban living can be rather pleasant. You can walk to get your food, kids can cycle around town, and you can sit and gather in public places that are designed for people instead of moving traffic.