I think this is crazy talk but I read an article that says football won't even exist in 25 years due to people just not letting their kids play anymore.
I can say that my son's private school (PK-12) has eliminated it all together this season and the local high school near my house (around 800 kids) only had 17 kids come out for the team this season so they will probably not have a varsity squad.
That article sounds like hair on fire chicken little recency bias tainted pearl clutching, to be precise.
There were times when people thought the same of hockey. Steroids and work stoppages were going to ruin baseball. A lot can happen over the years, and there's no shortage of people willing to take risks for glory, fame, and money.
I would say that kids who grow up as multi-sport athletes can learn football well enough in a year or two in high school or college. Youth leagues are probably more for parents than kids development. You can see the kids who are going to excel pretty early on in any league.
Parents and kids today are heavily influenced by the recent concussion concerns, and many younger people are eschewing traditional sports in favor of other hobbies. The pendulum can very easily swing back the other way in a few years as fears fade or changes occur in rules or tech.