I don?t understand why, when they don?t seem to have much competition.
Go through the list and see what is on the main ESPN channel these days:
https://www.espn.com/watch/schedule/_/type/upcoming/channel/e748f3c0-3f7c-3088-a90a-0ccb2588e0ed/startDate/20200917/country/usIt's all major properties. The CFL would be in huge "competition" for airtime with many other major sports leagues. Three hours dedicated to a CFL game is three hours that could be an MLB game or whatever else viewers actually want to watch in the US.
Pretend for a second the mighty AFL (Australian Football League) wanted to expand viewership in Canada. They get 25-35k fans out in Australia with a $12M-ish salary cap and the game is sort of similar to North American football (a little). The AFL figures, they just need Canadian fans to watch their games. They call up TSN and say, hey, we've got a deal for you. You can have the rights to all our games, no need to pay us. All you have to do is put it on the air. We've got the Brisbane Lions, Adelaide, Essendon. Lots of history (in Australia of course). Many great players too, Dustin Martin, Nat Fyte, Gary Ablett Jr.
TSN says, that sounds great but we've got targets to hit and ads space to sell. How many people are going to watch AFL in Canada? The AFL goes...probably very few but we want you to play it anyway for a bunch of years and we're sure more people will watch. How many more will watch then? No idea. But a bunch! TSN goes...you know what? We've got some NHL, CFL, NBA, Golf, SportsCentre and a ton of other properties that we know people watch and therefore can sell. Why don't you call us when people actually want to watch your product in Canada.
That's how it works. Obviously the CFL has a little more crossover as many players are from the US but it obviously hasn't been much of a hook over the years. At least in the mainstream... which is what you need to be to get on ESPN.