I disagree with the other reviews that make it sound like this is unreasonable: God withdrawing the hero status suddenly leaves Sam and Dean helpless and lost. Of course not everything they've ever done has been because of God, but most of it is.
This is my second time watching this show and thus time I did it all in 3 months. Had a lot of time and spent entire days just watching it.
There are a LOT of inconsistencies to the Supernatural world. It's often silly and ridiculous when you think about it. Of course, we don't, because we go along with the show. We suspend disbelief.
It's not that Sam and Dean never get cavities. That's just a funny way of putting it to drive home a point.
No it's about the fact that Sam and Dean (and the 'hunter' world) can go around impersonating fbi etc and almost never get caught, abd when they it's just another adventure: they always get out. They and their hunter friends can live without work, solely on fraud - and don't get caught. They fight monsters and are smashed around the room and the next day they don't have so much as a concussion or a sprained ankle. Even young girl like Claire. They're able to take hits from vampires and the like, and be just peachy.
That's just the basic stuff, nevermind the infinite number of close runs with demons, being brought back to life, going bro purgatory etc.
How is this possible? Well, it's not. Chances are, Dean is thrown against the wall by a demon and ends up in a wheelchair at the very beginning. Or they get thrown in jail and stay there for good.
But this isn't a show about prison or fraud. It's a show about hunting monsters. Sam and Dean, and the hunters as a whole, for the most part, get to go on fighting the good fight because that's the show Chuck Shirley likes watching. It's his favorite show.
Sure, they might be special in their own right, but having watched about 350 episodes in 3 months, it's clear their endless life-and-death adventures can only take place because Chuck wills it.