It certainly used to be true before 2007 and several decades leading up to it. Having up to a 25% unemployment rate brings down the US per-capita averages by a lot. USA ferility rate is also much higher than Canada's now (2 kids per female versus 1.5) which can throw out the numbers if not restricted to working age.
At this time Canada's per-capita income level is higher than the United States as is the Canadian per-capita GDP; it stands to reason that Canadian cities would be doing comparatively well over US cities.
Of course, I also expect this to revert again over the next decade once the US starts firing on all cylindars again.
The exception is the tech sector. The wages in the tech sector in the US have continued to rise, even through the recession. In fact, companies like Google, Oracle, Apple, VMWare, Red Hat all hired like crazy through the recession.
The truth is, Canada sucks for tech salaries, TBH. In Toronto, a senior software engineer will make like $60-$80k. In NYC or San Francisco Bay Area (aka. Silicon Valley), they'll make $200k+.
Anyone in the industry will tell you this. It's as true today, as it was before the financial crisis.
But the tech sector in Toronto isn't really dynamic at all. It's conservative, there's little risk capital, and Canadian companies tend to choose credentials over experience. Unlike the US, where a high school drop out with 10 years relavant experience can get a $200k offer from any major firm because they're desperate for talent -- that's of course, assuming they're talented as evidenced by they're experience. (I know plenty of software and web people like this who work in the valley)
In this industry, the talent still largely goes south.