In the days when sports teams were financed almost entirely by ticket sales the CFL and NFL were, financially speaking, on relatively equal footing and the CFL could sign top U.S. college football stars such as Johnny Rodgers and Joe Theismann. In fact, during the 1950s and 1960s exhibition games were played between CFL and NFL/AFL teams using a mixture of rules. The last such exhibition game saw the CFL's Hamilton Tiger-Cats defeat the AFL's Buffalo Bills, the only time in which a Canadian team defeated an American team in those series.
As late as the 1970s and early 1980s when high-capacity stadiums were built in Montreal, Edmonton and Vancouver and Toronto's stadium was expanded, people such as Montreal Alouettes owner Nelson Skalbania continued to believe that relative parity could be sustained so long as the CFL could get larger stadiums built in its other cities and sell them out. However, by the 1980s it became clear that financial parity between the two leagues was not going to be maintained - not so much because of the disparity in attendance figures as due to the NFL's increasingly lucrative television contracts that now bring in a majority of the NFL's revenue but because the U.S. television market is nearly ten times the size of that of Canada. The CFL could not hope to negotiate similar contracts with Canadian networks.
The CFL currently limits each team to 20 "imports," (i.e. players who have received training in gridiron football outside of Canada). In practice, nearly all of the CFL's "imports" are from the United States. [3]
Although the difference in average salaries is currently great, with only a handful of CFL players making above the NFL minimum, the differences in the rules between the two leagues means that different kinds of players tend to excel at each game. The result of this is that to a significant extent the leagues are not in competition for the same kinds of players. This has been evident in the 2006 season which has seen Ricky Williams struggle on the field despite the fact he was a star running back for the Miami Dolphins before being signed by Toronto after he received a drug-related suspension by the NFL. [4]