Yup, the CFL needs to start challenging the NFL for the amount of NFL crap that's out there ... though, it is getting better (I see more CFL caps than I used to, though it's very rare that I see another jersey on a non-game day, let alone one that isn't the Stamps).
Here in Calgary, the stores are mostly focused on the Stamps and Riders, with a bit of Esks stuff, in terms of CFL gear. But, it is possible to find another team's jersey in some spots. If you want a decent selection on other teams, you have to go to the Stamps Store, at McMahon stadium. Still, it's easy to find almost anything NFL, and absolutely anything NHL.
I see someone wearing some NFL merchandise and automatically think, what's wrong with the local (Canadian) league? What's wrong with your local team? Why can't you support the Canadian choice?