Ah, but if the NFL never came to an agreement with the now defunct WLAF (World League of American Football) then it'd be in a situation that's WORSE then the CFL's.
I remember the one (or was it two?) seasons when that league had American teams and it did POORLY all around in the North American cities. Interestingly the Montreal franchise did great business but that was before the Alouettes came back to the CFL (They were folded after the '85 season and they weren't even called Alouettes. They were the Concordes!)
Anyways WLAF went away for 2 years where they came to an agreement with the NFL to be a feeder system of sorts and got repackaged as NFLE. The first few years there wasn't even broadcasting in North America except for the World Bowl.
The NFL has a financial arrangement with the CFL and there is a stronger symbiosis between both leagues as the NFL often takes fliers on CFL talent and when NFL cuts are made every CFL team brings in at least one guy or two because they didn't get a chance due to size or whatever in the NFL.
Anyways I found this neat comparison of both league's rules and stuff (getting page)
Comparing Canadian and American Rules:An overview for fans with some previous knowledge of either system
I found it on a CFL fan page but it's pretty objective for the most part tho the guy got the part about timeouts in the American game wrong as 2 minute warning is in both halfs.
Anyways take a look.