You misunderstand: It's not about choice or preference, it's about increasing quality of life. Supposedly "suburbanites" decrease your quality of life. But wouldn't forcing others to live in a more cramped neighbourhoods be decreasing their quality of life?
And new suburbs are already being built at very high densities... about as high as you can get for single family homes. Streetview of northern Markham:
http://maps.google.com/maps?client=firefox-a&rls=org.mozilla:en-US:official&hl=en&tab=wl
Also, moot point, but for the sake of accuracy, it's cheaper to deliver goods (say milk) to suburban grocery stores than to those in high density neighbourhood. I could explain why but it'll take more sentences than I'm willing to write right now. Please refer to a geography textbook if you're interested.