While I agree that this trope can make kids think they're special without trying in life (and that they will be a hero in the future), I think there have been similar tropes in the past.
Just take basic story writing of many old movies: There is always a hero that is living a boring or even sad life, often unsuccessful and unhappy. Suddenly, a "mentor" appears who takes our hero into this new magical world and teaches him the most amazing things in no time. Matrix, Star Wars, Harry Potter, basically all Disney movies, even Sailor Moon.
That doesn't teach kids very positive things either: just wait for a mentor to come along and show you the way to become a hero, don't worry, you will be a hero because someone shows you the way.
So I don't see the development described in the YouTube video as dramatically, it has existed forever.