Yeah, but that's not really a fair comparison. Most webcomic folks don't have the resources that Penny Arcade has. They're frequently one-man operations where the cartoonist serves as the marketing, PR and customer service rep. They're probably working a day job on top of that and some of them have families. Oh, yeah. They also have to make the comic.
That kind of commitment is overwhelming to a lot of people. Frankly, I don't know how I managed to keep most of those plates spinning for nearly a decade. I've dropped a couple, of course. Community management being one of them. But I think I've managed to retain my core supporters. It's just a matter of prioritizing what you enjoy doing and what you're good at. It's a bandwidth issues. Some guys are only good at the comic and that's it.
Incidentally, I'm not making excuses for shoddy customer service, community management, etc. etc... I'm just a little more understanding of it having been one of the sleep-deprived, unwashed ilk.
Truthfully, 99% of the fans are just as understanding so long as you don't abuse their trust. It's just a matter of keeping the lines of communication open, being honest and keeping your cool. Not hard.
Incidentally, I've seen Khoo speak and he talks about how other webcomics laments that they don't have "their own Khoo." It pisses him off - and rightly so. Khoo greases the wheels, but no one would be attracted to Penny Arcade if Mike and Jerry weren't producing a high quality product.