I think the big problem with football at it’s lower levels is that it just pales in comparison to what the NFL and Major College Football do to perfection. They have the TV contracts and the cheerleaders and the marching bands and the flyovers and the coveted weekend time slots. Lower level leagues have none of that, and that exposes the real flaw of American Football - purely as a game, stripped of all the associated pomp and circumstance, it kinda sucks.
Football requires a lot of players, too many officials, the rules are extensive and often too subjective, and it is prone to injuries and violence. Women don’t have anything like an equivalent sport. Think about it - outside of throwing a ball around, you almost never see anything resembling the game being played outside of highly organized leagues. Sure, there are some flag football leagues around, but they are generally populated by guys in their early 20’s who don’t play the game for more than a year or two before moving on. Compare that with basketball, which is played as a pick-up game indoors and out, and organized leagues are all over the place, for men and women of any age. They have leagues for guys 50 years and up. Same for softball, baseball’s gentler cousin. Soccer, too. Hockey is a little tougher due to finding ice, but pond hockey is always being played in Canada and the Northern tier of US States.
There’s a reason American football hasn’t spread outside of North America while basketball is universal. Basketball needs a minimum of space, even a single hoop will do. You don’t need a lot of people or equipment, and the rules are simple. Soccer is the same. Baseball needs more space and equipment, but it has taken off in Asia and the Caribbean/Central America.
Football, stripped of it’s other sources of entertainment, just isn’t that popular either to spectators or participants. FCS football, the second tier of college football, but still a high level that sends multiple players to the NFL every year, averages under 10,000 spectators, and that is skewed by a dozen or so schools that are the only game in town and have high attendance like the Dakota schools. A FCS game with median attendance has about the same number of spectators as does a single A baseball game.