there is so much more that can be done with hybrids.

the main drawback of conforming is that you can either have a 50 meg piece of clothing with tonnes of preset morph poses, but then its inevitably still not going to look as good as dynamic, and wont be suited for any poses that havent been accounted for in the built-in morphs.

the problem with pure dynamic is that most of it that isnt skintight, IMO, looks nowhere near as realistic as the characters we use it on. even if there are rudimentary seams, cuffs, etc it still comes nowhere near properly modeled conforming clothing. it also brings its own issues with pokethrough, jaggies, etc... in order to have a piece of dynamic clothing that folds and wrinkles well youre going to need a mesh far more dense and less optimized than the average conforming clothing item -- yet still with far less detail.

hybrids bring the best of both worlds together... you can conform the tight-fitting parts and those that are better suited to conforming, and then have loose flowing or draping parts that are dynamic and will animate better, look better, drape better and be suited for almost any pose.

i think that until now many people avoided dynamic clothing because it seemed like a hassle, and also not all of the dynamic clothing on the market is very appealing... but now that everyone should have at least poser 5 (come on, it was free... there is no excuse anymore) and dynamic capability more merchants will be using it and more customers will be open to it.