Well, that's the entire population. Half of those are above the age. Only around 15% of those are at the game where their football career starts. More than of them are females, so 7% at best qualify as male in the right age. If any of those people are interested in a sport it would be Badminton more than football.

Consider the quality of facilities, development programs, managers, league competitivity, and youth sports center and it is not 256 million, more like 1 million, barely. No country in the world won titles thanks to its population.