The amount of luck required to create a dynasty is insane. You need a once-in-a-generation QB, great coach, and great GM who all work exceedingly well together.
I don't think it's an NFL thing, just an aberration. (And I'm really glad it happened to the team I root for.)
It could happen. Patrick Mahomes is only 28 and has already gone to four Super Bowls. It's not unlikely that he'll go on to win more, provided the Chiefs pay Veach and Reid a lot of money to stay.