There is an economic bond in that some provinces annually give a hefty bonus to other provinces ... the country works together to remain unified. The entire country has to buy their oranges in Florida.
OK, but then you're talking about legal culture, and that I think we've already establish is indeed a shared culture from coast to coast to coast. It is mandated by law. It still doesn't change the fact though that unless you know Inuktitut, you'd have a difficult time adjusting in Kugliktuk, not just because of the climate, or the geography, or the smaller population, but because you'd likely have a hard time communicating with at least some of the members of the community. You'd have an even harder time in Tadoussac because they all speak French, and with French being a major world language too, feel even less of a need to learn English, especially with no English-only speakers for 100s of miles around them.
Simple trade and common laws don't make a solid foundation for a common culture beyond a simple civic one. Remember that French-Canadians even have their own version of the national anthem, with many not knowing the English version, and with some also singing's one of Quebec's unofficial anthems, such as Gens du pays.
Just to take another example of Canada's lack of a common culture, do you know Gens du Pays? Do you know the famous Quebec poet who wrote it, Gilles Vigneault, along with his main literary influences which come not from Canada, but from Hugo, Beaudelaire, Verlaine, Ronsard, Rimbaud and others from across the pond in France. Though he is well known as a poet in Quebec and possibly in France, he's practically unheard of in English Canada. Likewise I'm sure there are plenty of famous English Canadians such as Loreena McKennitt who are barely known in Quebec except in the Anglophone parts, even though she's likely known in the UK, the US, and even Australia.
We certainly don't have a common culture beyond a civic one.