I don't think anyone is claiming that housing density is the only dimension of city planning. It's just the most controversial one. Transportation, schools, and

I don't think anyone is claiming that housing density is the only dimension of city planning. It's just the most controversial one. Transportation, schools, and grocery stores are also required in the right proportions. It's also a big deal how all these things are placed. If homes, offices, and retail are nearby then people need to travel shorter distances and transportation gets easier.