It's completely disingenuous to mark the rise of the NDP in 2011 as being exclusively in Quebec. The NDP became the first or second choice pretty much across the country, and their gains have held across the board or improved in every part of the country as well. If they lose seats in Quebec in 2015 it probably won't be many and they will probably pick up elsewhere.
Again, your extrapolations make no sense. They assume the conservative voting base is unable to shrink or shift.
The vote splitting that ruined the Conservatives chances in Ontario is what's going to damage the NDP/Liberal voting block the next time around. Besides, as we've seen over and over again, just because someone gets a certain percentage of the vote, doesn't mean they get an equal percentage of the seats. Polling (and by implication popular vote) is an indicator, but it also doesn't tell us what happens on a riding per riding basis.
Now I don't know anything about East Coast politics, so it's entirely possible that voters in the Maritimes are much more fluid and aren't tied to any particular party. Maybe we'll have another Danny Williams tell voters in their province to vote anyone but Conservative because of some bad deal the Federal government is trying to impose on one of the provinces. But that seems to be the only real place where serious gains can be made for the NDP... and even then, seat wise, assuming the Conservatives keep most of Ontario, it's not enough.
Of course, I also understand that not every Liberal vote is an NDP vote. If the Liberal brand died, some of them would move to the Conservatives and some may choose not to vote. But people probably said the same about CRAP (sorry, I will never let that go) and PC supporters after that merger and... well, if you're not voting for the new Conservative party, all you are doing is cutting off your nose to spite your face and denying yourself a vote.
The PQ is a rather left-leaning, and the NDP is too most of the time. It makes sense there would be a voting base for them in Quebec that won't leave them on a whim. Harper is seemingly making sue of that.
I just wonder if a Federal party can support itself without any local support. I mean, we all heard the stories of candidates who were on vacation or who didn't have any offices in their ridings because they just assumed that they would lose. I'm sure the NDP is pouring a crap load of money and man-power into Quebec to beef up phone banks and all that logistical stuff, but this is something that's much easier to do when you already have Provincial and Municipal party structures and people to rely on.
I'm assuming that, for instance, the PQ isn't going to hand over voter lists and whatnot to the NDP just because they share similar social values.