I can't speak for all of Canada, but here in Toronto there is evidence that the mindset is finally changing. There was a poll in the Star in the days after the municipal election stating that something like 46% of the population feels very strongly that Toronto needs rapid transit expansion to deal with ever increasing gridlock. Only a small minority felt it wasn't a serious issue. And with the constant related articles the Star pumps out and things like the Soberman report, awareness of the potential disaster if we do nothing very soon is only increasing.
I have little doubt that the central cities and older suburban regions of most major cities do want more transit, be it Toronto, Vancouver, or Montreal. In Toronto, this has always been the case. Articles about the need for transit, plans, problems, and other issues involved have been published in the paper on a regular basis for at least the past 10 years (probably even before then but this is the time span that I have spent observing this trend and reading the articles).
The problem lies in all the other suburbs, cities, and munipalities surrounding Toronto (Markham, Oakville, Hamilton, Oshawa, etc) and the other cities across Ontario (London, Windsor, etc), excluding Ottawa however. Toronto can vote in as many pro-transit provincial and federal government representatives as it wants, but if the rest of Ontario and Canada vote against this trend and hold the majority of power of this decision, then it really doesnt matter who Toronto elects in the end.
Really there are two most likely scenarios for increased support for transit. Either the current system breakdowns, perhaps because of rising fuel costs, congestion, or some other event, and through this breakdown causes people to demand solutions to the problem, which could very well lead to greater increases in funding for transit. Or, pro-transit advocates, related businesses and industry, political groups, and cities such as Toronto with a strong interest in public transit develop a better system of education and propoghanda to send their message to the rest of the people in the province who dont see the daily rant about transit in The Star.
Until Markham, Vaughan, Mississauga, et al vote with Toronto, instead of against Toronto and residents in those parts of the GTA want public transit as much as the citizens in Toronto do, there is unlikely to be a government that is going to really do that much about the problem.
Unfortunately, the problem with, and lack of, public transit has become such a problem that it is not just going to be solved by small or medium sized measures. It is going to take a rather dramatic amount of capital, construction, and rethinking of how people move in modern Canadian cities. This also adds to the difficulty that is faced by those wanting to push forward transit policy.