The question is generally about where to house people, I guess.Answer to what question? We can't continue with the 1970s-90s scouring of farm and forest land to build SFHs.
Whenever I fly to Germany I note from the plane how much green space there is between towns and cities. Somehow Germany fits over 83 million people into a country with half the area of Saskatchewan but keeps its rural and agricultural areas. They do it through density. That's the answer you seek. Alternatively, we have a huge country that is sparsely populated - we don't all need to live in the Golden Horseshoe.
I applaud the development taking place along arterial road corridors and in the downtown area, but eventually all that low-density single-detached residential areas in the City need to be addressed. They aren't there for market reasons, they are there because of government intervention via zoning.
Yes, density is the answer, but more specifically, we need to change our built-form, because you can't build density with this typical inner-city Toronto built form. We need to allow those neighbourhoods to transform themselves into something more like this typical built form found elsewhere in the world.