We know they all love the attention, but which decade was it that they moved away from "practical with luxury" to mostly "wacky shock value" stuff?

Mossimo? We all know what happened to him.

Not all of them have.  But here are three facts for you to consider:

1.  Many of the pieces (sometimes nearly all of them) shown by a designer are not intended for anyone to actually buy and wear.  Rather, they show the development and exploration of a theme or an idea for which they hope their line will become known.  Actual, real clothes come later.  In such cases, the clothes shown on the runway are similar to the concept cars shown at car shows.

2.  The purpose of a show is often not to sell clothes per se, but to make the designer known (or keep them in the public eye).  "Practical" isn't the best way to do that.

3.  Some designers have little intention of selling clothes at all.  In fact, in some big fashion venues such as NY Fashion Week, the designer actually makes money on the show by promotional tie-ins and sponsorships.  In those cases, the show is the product, not the clothes.