The Goldeyes and Moose 1.0 both played with the same rule sets of the big leagues and had little to no success with younger fans. Goldeyes is full of seniors out for a nice night out and the Moose had lots of younger families also out for a cheap night out. You never saw 15 - 40 year old people wearing jerseys or merch or talk about them. I saw way more people my age associating with major league teams (Leafs, Blue Jays, Habs, NYY etc...).
It would be completely ignorant to think that the reason younger demographics gravitate towards the NFL over the CFL is because of the difference