A friend of mine did some analysis. To support a subway, all other things being equal:
(1) with (50%+) significant subsidy you need at least 4000 people per square kilometre to support regular service.
(2) with less subsidy (33%+) you need at least 7000 people per square kilometre to support regular service (Singapore density).
(3) without subsidy/recover costs entirely from the fare box, you need at least 25,000 people per square kilometre.
I can provide spreadsheets with the amount of population and housing increase each ward would need to get to these levels. Meanwhile, Denver has made LRT work with federal funding for less than 300 people per square kilometre, which is like Detroit wasteland density.
With permanent gas tax/50%+ subsidy, it might be possible to make subway work all over the city by 2036, ignoring the actual capital cost, or mobility issues of an aging population.
With lesser subsidy, we’d need at least 4.5 million people in the current Toronto to make it work, which is at least a million extra people than any population projection envisions – and all the work he's been doing here suggests the government projections are way too fucking optimistic already.
With no subsidy we’d need about 16 million+ people within the current Toronto, which I can’t even begin to imagine.
This is all going into a letter for city councillors. Particularly those undecided and openly against Transit City.
It’s great they want subways. Who doesn’t? But the development they need to allow to make sure it can fund itself is astronomical. Plus, with an aging population, each and every inch of all the subway stations better be 110% accessible or people will be trapped in their homes because they’ll all have their driver's licenses pulled/and or can’t afford gasoline on their pensions.