This analysis misses the knock on effects of the oil economy. In Calgary or Edmonton for instance, the centre of the oil economy in Canada, all jobs depend on oil. If you don't work in oil but work in a geographic region fuelled by oil profits, your profits will drop as well. All retail and most all service industries are being hit.
Canada was absolutely enjoying an oil boom. It can be hard to see the connection between a new highway or hospital and oil prices at 100, but rest assured they are intertwined. Yes people who owned oil production facilities benefit most as they took on the most risk, but all of Canada benefits when they do well. It is sort of like being a cafe owner in Silicon Valley saying, "I'm not sure how I, as a normal hard working person, benefits from all these rich programmers around."
Further, oil revenues are a major component of the tax base to Federal and Provincial governments. With those revenues drying out, transfer payments to non oil provinces, and social programs across Canada are threatened. Oil is absolutely fundamental to the Canadian economy at this point.