"It would do little to de-bifurcate the GTA’s housing supply, which currently offers home-buyers a choice between a small condo in a high-rise or “drive-to-qualify” for a detached house in the suburban fringe"

Not true.  Condos in a high-rise do not have to be small and many are not. Most families around the world, including here, live very well in 2 or 3 bedroom apartments. Surely owning instead of renting a 2 or 3 bedroom condominium works just as well. My family's first home was 3 bedroom, 1,000 sq. ft. bungalow. Worked for 4 just fine.  But that was 1962.

Can't find that starter bungalow today, buy a starter condo of the same size. And walk to work and school.