I think Culpepper was a good player. I think he did benefit from having some good offensive players around him, but so did most good QBs.
Whats interesting about Culpepper is that when you expected him to do bad, he was great. And when you expected him to be great, he sucked. Lets be honest...his first year as a starter in 2000 is one of the best "debuts" in NFL history. As KOF said, no one could bring him down and he had great WRs to throw to. He followed that up with two pretty bad years, and his decent 2003 season is tempered by the fact that he fumbled so much. Thats one of my most vivid memories of Culpepper...him fumbling and the announcer explaining that "he has small hands". But when you thought he was finished, he had an incredible 2004 season with only partial help from Randy Moss.
I view Culpepper to be somewhat like McNabb. His "wild card" was his mobility and strength. Once he lost that, he was a below-average QB. I think even without the knee injury, just the natural aging process would have affected Culpepper's game and his numbers would have nosedived pretty quickly. So with that in mind, I would say Culpepper's realistic possibility for the HOF was pretty low.
That said, Dave isn't THAT far off with his line of questioning.