Why would it be unsustainable?
You're kidding right? Are you unaware of the massive differences in
ridership and property rights for
JR and
MTR? Or the
bailouts (about half a trillion in CAD in 1987 dollars) that Japanese railways received? MTR and JR were/are heavily publicly financed property developers who happen to run rail networks. Go through their balance sheets and look at what happens if they were limited to running rail networks exclusively.
Put that much money (proportionally) into rail in Canada and give the rail operators the same property rights as Asia and they'd be successful too. Imagine, VIA, Metrolinx, AMT, etc being some of the largest developers in the country, and doing so on the backs of $110 billion (1987 dollars) of public investment. Nobody would ever need to own a car in Yellowknife, if that happened.
There's also the geographic context. In 1987 when JR was bailed out, the population of Japan was over 120 million, and the population of Tokyo was about 12 million. With Tokyo gaining another 2-3 million during the daytime. At the time the population of Canada was 26 million. In 1981, the population of the entire Toronto Census Metropolitan Area was just shy of 3 million, for an area of ~ 5905 km2. In the same year, Hong Kong had nearly 5.2 million residents, in an area of 1108 km2. I really don't get how people can think models that work for Japan and Hong Kong will easily translate to Canada, given the massive contextual differences.
It's become routine now. Every few months some new member joins and bemoans why we can't be like Asia, while being oblivious about everything from the difference in governance, geography and economics between Canada and those places. We cannot and will not ever be like Asia because the historical, social, economic and geographic contexts are entirely different. And insisting on comparing only to those places does more harm than good, in my opinion.