For the record, I'm a bit younger than Bob, so I got to know Kevin Smith all at once in high school (around 16-years old I discovered and quickly bought the DVDs of Clerks through Dogma). The dude was a legend in my eyes for many of the reasons in the video, but as soon then Jay and Silent Bob Strike Back hit, I twigged to who Smith really was and what he was going to be (watching the DVD commentaries really helped get into his mind). I think that was the last Smith film I saw, though I still regard him fairly well as a filmmaker (in a certain context).
Now, though, he's mostly a gadfly on nerd culture. An apologist for studio insiders too wrapped up in the fandom to be an effective creator of the sorts of things he actually likes to talk about. Ultimately, though, the disappointment with Kevin Smith (and it is certainly warranted) probably comes from the horrifying revelation to snarky nerds (and I include myself) that we are somehow incapable of producing the sorts of things we loved growing up.
There was a time when some nerds thought: "One day Kevin Smith is going to write that amazing script for a (insert favorite comicbook character) movie and it will usher in a Golden Age of CBMs," especially after his account of nearly writing Superman Lives. But now, that Golden Age is sort of already here, brought about by people who don't actually have an obsessive love of the source material, and Smith has demonstrated that he probably can't even write a decent arc for the books themselves.
Smith proves that a meticulous understanding of genre fiction, comparative details between franchises, and an overriding desire to push the puritanical boundaries of "good taste" will never ever produce the next Star Wars or Marvel comics. Generally speaking, the things we loved as children and consume our identity as adults were created by upbeat idealists steeped in broad mythological narratives, not prickly loud-mouth know-it-alls...like us. And that's sort of infuriating to people who have put all their eggs in that basket.
In 20 years, Kevin Smith will be mostly a footnote in the broader culture. Maybe, just maybe, the aesthetic of Jay and Silent Bob will remain a stock visual gag (though even that is essentially just a modernization of Laurel and Hardy). But the adults then (who are kids now) will look back at people like J. K. Rowling and Pendelton Ward as the shapers of their generation... I assume. (Frankly, I don't even know what the kids are watching nowadays.)
I don't listen to Smith's podcast, I don't watch his movies anymore, and I won't read any comics he writes. Not because I have any personal animus toward the guy, but because he is too often just an echo of myself. He is the end-result of pop-culture, not a source.