This concept and original analysis is totally flawed. The basis for the rush to downtown is the convergence of two demographics fighting over the same housing.
I understand the fantasy land some people want to live in. The “wouldn’t it be great if this was Paris and everyone walked” I’m sure that keeps the coffee shop talk exciting.
Downtowns are popular with single people, young people, gay people, hip people and childless couples. What they are not popular with is old people. The old people in the city are the people that have been there forever and don’t feel like leaving. They don’t move there in large numbers and they won’t.
Urban areas also attract poor people, crazy people, hobos, homeless people for a variety of reasons but these people cannot handle the difficult task of vehicle ownership, maintenance, insurance and licensing. So they will always be in urban areas. Old people for the most part are afraid of these people.
The other element of a downtown residence is that it is close to work, retired baby boomers (who will be 70 in 2016-2018) are not going to pay 3x the price per square foot to be close to a job they retired from, that’s just stupid. Plus the stores and restaurants are more expensive. It’s noisy, crowded and busy, the exact opposite of what old people like. 70 year old people don’t hang out in gas lamp bars, dine in stylish cafe’s and shop the hip stores. They play golf, travel in motor homes, hang out with other old people and try to live as nicely as they can afford. $800 hoa’s of downtown condos are not real popular with the fixed income crowd. So places like Phoenix, Oregon, Idaho, Palm Springs or even Rancho Bernardo are more appealing to retirees. It has what they want.
But have fun with the “wouldn’t it be great” fantasy.