Isn't this pretty much true by definition, though? People who want density will tend to all go to the same relatively few places (that's how you get density), whereas people who want to avoid density will go to different places (because if they all went to the same place it would become dense).
Most people have much more complex wants and density if at best a small part of the picture.
People want the best of all worlds. I want to own 100 acres (for my pet goats - even though I don't have the time to care for them I want them). I want my kid's school to be a most 200 meters from my front door (with a playground). I want my office, church, a dozen restaurants, and 30 other retail stores to be at most 500 meters from my front door. I'm not rich enough to afford that though so I have to compromise. Even if I was that rich, it is not possible for more than 2 people rich enough to afford that to live within 1000 meters of each other, and to support that requires thousands of not rich people living in 1000 meters.
People will choose a walkable neighborhood when they think it is a good compromise. Some valuable large livestock more than others and so will be late to move to the walkable city. Others want to spend their free time at the theater and will move to the walkable neighborhood early just because it is the fastest way to bed after the late night show. Most people are not so into either choice that one answer is obvious.
If you want a walkable neighborhood to work you need to fix the local schools. At least in the US most walkable neighborhoods are old areas of town where the schools are bad, those who want children feel compelled to move to the suburbs and the car lifestyle just because of how much better the schools are.
If you want walkable neighborhoods you need to fix zoning so that it is possible for them to happen. Strongtowns has a lot of analysis of what makes it possible - there are thousands of subtle things required, heavy handed efforts tend to leave a lot of the subtle problems in place.
