I have a hard time thinking of the bridle path as sprawl. Aside from its urban planning/geography usage, sprawl is a word that has a definition...here is one version of it " To spread out in a straggling or disordered fashion"
Implied in that is that it is an outreach...that it makes the city bigger and extends its boundries. I don't think the bridle path does that at all.
Is it low density...sure......is less "urban" than the majority of the city...yes.....is it sprawl....IMO, no.
So I'm just trying to understand this definition of sprawl. Right now, Springdale is sprawl, because it's on the suburban-rural fringe of Brampton, but if all of Caledon gets suburbanized, Springdale is no longer sprawl because it's surrounded by development and therefore not causing the city to be bigger? The Bridle Path was sprawl in 1960, but no longer in 2010?
As for whether or not it would lead to more sprawl if following the Manhattan model...
So the assumption is that currently,
Super rich household takes up 2 acres of space in the Bridle Path
Manhattan Model
Super rich household takes up 0.01-0.05 acres in a luxury condo or brownstone in the core, plus 2 acres in King (or some such).
So yeah, the current model would take up about 1% less space... However, there are at least some advantages of having the highest densities in the core with gradually decreasing densities as you go further out (Manhattan model). Mainly, it means that transit doesn't have to be built as far out, because the majority of the population lives closer to the core, with only a small percentage living in the low density fringe.
And...
All of this assumes that the people who live in North Toronto and South and Central North York in big single family homes don't own a cottage in the Kawarthas or Muskokas, which they probably do. If they already have a place in the city core, I'm not sure they would need an estate retreat in King plus a cottage retreat in the Muskokas.