Wow, this is pretty much the wavelength I've been riding on for the better part of season 2. I believe we are supposed to see the show and everything that goes on within it through Sam's eyes (or at least to an extent), but there has to be something big in regards to Dean. Like you said, why is he still alive? So the YED can get rid of Daddy Winchester by trading lives, but still, he could have lied about it and just let Dean die too. I mean he shows John that Dean lives but as soon as he gets the Colt and John, bam! Dean is a goner and Sam is left to what? Give in, perhaps.

At least to me, that could have easily happened if Dean is so insignificant as the YED so contiuously states. But it didn't. And unless Kripke and Co. didn't realise how they were making Dean look, and it's just an accident this stuff appears as it, does, I think there has to be more at work here.

I really think there is (or there should be) a firstborn correlation and that's why Mary knows the demon or something like that. Basically what you wrote. Which is way more elegant than anything I just typed up.

This was a really interesting post. Thanks for it.