I would think more people play Youth and High School football would be higher than the combined amount of people who play youth hockey. The United States is massive population-wise, and outside Russia and Canada, most of the other Hockey nations are quite small (Sweden, Czech Republic, Slovakia, and Finland). Even then, Canada is about the size of California population wise. It's growing in some bigger markets like Germany, but the player base still isn't large. Due to how Football is funded, it is a way more accessible sport to play. Whereas people who go far in hockey are generally skating by like 4 or 5, and playing on expensive travel teams by like 8. It requires a unique skill set, whereas Basketball and Football require more freakish athletic ability that you can get a late start on if you have those attributes.