I think the biggest issue is the fact that the beetle will always be deemed the "cute" car. So less after market companies make body kits, extra parts, parts to increase speed, performance, etc.
Unless you were in absolute LOVE with the NB body, why would you get a NB when you could get a Golf, or GTI ???
Don't get me wrong, I love my NB and I can't wait to make him a "non-cute" car. I want him to be a "sleep", a slug bug on the out side and speed demon on in the inside.
But think about it. NBs hardly get respect from other VW people. Anyone ever been to a VW GTG, not NB specific? We're the "round ones". Beetles don't fit that sporty, racing, ricer type feel. Probably why they sadly got rid of the Turbo S, CC, and Diesel. VW probably realized that Beetles were "cute" and marketed them that way.

As some of you have noticed, the fun, bright colors have disappeared, and now we're more into pastels and soft beige, etc. Only makes the car "cuter". It's no longer a revolutionary, re-live the past, kinda car. Plus when the convertible came out, the NB because a cute, mid-life crisis kinda car. And most women in their mid-life crisis want a convertible but dont' want a bright noticeable color. The brightest they would want is Red. So, pastels and beige came along, made the car look softer and more girl friendly. The auto tranny proved to also be girl friendly, for those that refuse to learn how to drive a stick. A soft pastel NB convertible with an automatic and no turbo proved to be a comfortable, cute ride that isn't a sport car. And of course they came out with the "new" body style. The flat sided fenders, thin streamline blinkers, little (what it looks to me) rainbow brakelights (when they light up), all tried to make the car classy/cute. Removing just about everything that resembled the car to be a "sports car".
I read somewhere that VW was going to remake the beetle and make it more "american-ized" with bigger cup holders, bigger seats, maybe even a 4 door or something like that. So that the beetle FIT the American people. If I wanted American fashioned cars, I'd buy Ford, Chevrolet, Chrysler, Dodge, etc. I want a German car, with German features! As much of a pain that my cup holders can be, I prefer them over bulky holders that can hold up to a 64oz drink!
I know VW is just trying to stay in the market, and it's working. It's just sad because of course, we are losing what makes VW so great. I think VW is stearing clear of being too flashy, cause that's not what people in the US want. Look at the majority of car colors. I bet you'll see....white, grey/silver, black, red....more than ANY other color.
Glad I have my 02 diesel. I love surprising people with the soot screen, or when I'm filling up at the station. "It's a DIESEL?!?!"

Yup...it IS a Diesel.....