As a Torontonian, I support this.

As things stand, you can walk faster than drive the Gardiner during rush hour, and the thing's crumbling anyways. On top of that, most of it is completely surrounded by sky scrapers anyways, so it's perfect for high rises. The Greenbelt is only going to provide 50k homes, out in the middle of nowhere that also requires roads, electricity, water, sewage, and probably more infrastructure. Aparently that alone will take 25 years to install, not to mention the millions of dollars. All that is pretty much already there around the Gardiner.

And as for the number of housing, 50 floors with 30 units per floor means that you need 33 buildings to get the same number of homes, and each building can be put up in under a decade, if not five years. Not only is it far faster, but cheaper and easier. And the tax revenue would be massively higher. In fact, I imagine that greenbelt homes wouldn't even have a positive tax revenue due to all the infrastructure needed to be built first.

Greenbelt housing not only is low quality, expensive, and too far away to actually be able to reasonably commute to any sort of job, but actively harms the environment, risks doing lots of damage to nearby cities in the far more recently frequent major weather events, and can be done easier, fast, and cheaper by simple alternatives like the one proposed here.

Greenbelt housing is political corruption at its finest.