It seems to me that the incentive-difference is that in the US, the tax code is telling you to flip often, or not flip at all.
Another big difference in tax policy, if I recall correctly, is that Americans don't pay tax on mortgage interest. Seems to me, that incentivizes Americans to over-leverage on paying mortgage interest. Don't worry though, in Canada these days, we too over-leverage on mortgages, because otherwise we're homeless, as per the article. I sure wish I could tax-deduct my mortgage interest, because that's the main thing I spend money on.