Not sure if a disposable-income denominator is fair when there are such large discrepancies in taxation and public provision of big-ticket expenses.
If you get taxed harder in Canada but then don't have to pay for healthcare or education privately than in the US, then it makes no sense to just say 'look disposable income in Canada is lower, thus debt:disposable income is higher, thus Canada is worse off'. You'd first have to correct for the fact disposable income is lower because taxes are higher, because healthcare and education are publicly financed and therefore individuals require less disposable income and could be just as well off.
Second, just look at mortgage delinquency rates between the US and Canada for an impression on affordability.[0]
Third, debt doesn't matter much, not all debt is made equal. A 15% creditcard loan for $10k is much worse than a $20k 3% loan, in terms of bankruptcy risk, even if the debt to income ratio is worse on the latter loan. You can't just look at debt to income, and again, especially not disposable income between countries which very different systems without correcting for it.
Absolute debt doesn't say much, debt servicing does, and in particular servicing of interest rates. That's actually at historic lows for Canada [1], which is totally different from the US[2]. Canada's debt servicing ratios are much lower than in the US. And that's why, in part, the delinquency rates are much, much lower, and why it's not quite so simple to conclude that Canada is in a RE bubble compared to the US.
[0] https://i.insider.com/596f5f88a47cb502028b4f17?width=750&for...
[1] https://www.macleans.ca/wp-content/uploads/2014/03/can_mort_...
[2] https://www.macleans.ca/wp-content/uploads/2014/03/us_mort_d...