I'm not saying I dislike the Hitchhiker's books - they were probably my favorite things in the world when I was 12-14 - I'm just saying that I don't really get a lot out of them, and always sort of roll my eyes any time someone older than 20 goes on about how genius they are. I think it's a bit of rose-colored-glasses mentality. Hell, even into my early 20s I would fondly remember the books. Then I went back and re-read them, and I was kind of like... Oh. Yeah, this is pretty good, I guess. But by then I had moved on and was more interested in things that were either more funny (Pratchett), more serious (Irvine Welsh), or both at once (Pratchett again, or Stephenson, or Robert Anton Wilson).
In fact, RAW is a pretty good comparison in what I've perceived as fanbase and trajectory. Adams seems to me to be held up and beloved by, for lack of a better term, geeks. Not in a bad way, just... you look at the Illuminatus! trilogy, and there is a series of books which Hitchhiker's in many ways paralleled (Hagbard Celine and his golden submarine are almost directly analagous to Zaphod and the Heart of Gold, a main character who is clueless and ripped from "the normal world" into a completely zany and unbelievable adventure, etc. - no idea if Adams read the Illuminatus! or not, but the parallels are there). But you look at the core fanbase, and from what I've seen, the core Douglas Adams fanbase are people who are slightly "wacky" but tend to be in bed by 11 and would have a nervous breakdown if they went to Burning Man, whereas the core RAW fanbase are people who take drugs and get into entirely outrageous situations on sheer whim and with frightening regularity, often with tragicomic results, but still.
Basically, correctly or not, I tend to think of adults who are die-hard Hitchhiker's fans as being a convention hall away from Trekkies, and usually when I meet such people I really think they ought to loosen up, go wild, really live the dream.