The working class in the US has certainly suffered a regression over the past several decades, while the upper class gained tremendous amounts of wealth. One might assume the wealthy seized their gains from the middle class, and this may be true, to some extent.
However, once you widen your lens to a global view, you will see poverty world-wide drastically improved over the same period of time. So the regression of wealth away from the middle class in the US might more accurately be considered as transfer of wealth to the rapidly-industrializing world.
If you are referring to something different that's been happening in Canada, I apologize. I am not very familiar with Canadian history.