There is no way that Canada had more talent than the Soviets in Canada Cups in '81, 84, and '87. The Soviets blew Canada off the ice in the Challenge Cup of '79 and the '81 Canada Cup. Canada won the '84 and '87 Canada Cups in Eagleson's office, not on the ice, although the margin of victory on ice was about half of a nose hair. The Eagleson-appointed American and Canadian refs panicked in '84 and '87 as the crowds made all the critical calls. The Soviets sent B teams in '76 and '91, so that shouldn't count - or, should we start adding WC Gold into the mix.
In modern times, although the margin is narrow, you can make a sound argument for saying that Canada has been better than Russia of late in the Olympics, but you can't say the same about the US. Almost all the teams are close to being the same, with Canada having the slight lead, which they will likely protect with home ice advantage in the World Cup.