The difference is marketing.
If you took Skullcandy drivers, put them in a fancy aluminum enclosure, added an Etruscan leather headband, tarted up the package, rolled out the marketing (including shills and viral marketing - print/banner ads are passe and recognized as ineffective by almost all ad agencies) charged $700, then they'd get attention. Especially the price tag - you'll see price frequently used as a mark of quality here. It's assumed that there must be something to justify a $700 price tag other than increasing the margin.
That comes across as excessively cynical, I know, but consider the various headphones made for professional use. There are many excellent pro headphones that are barely mentioned here. Some of them are, in my opinion, far better than headphones typically recommended here. Why? First, and most importantly, they're not marketed to this audience. If there's no beating of the drums (viral or otherwise) there's an assumption that the gear isn't up to the quality of what is being promoted. Second, the prices are often "too low." When "the best" costs $1,400 or $1,700 (regardless of cost of production and overhead, mind you), then a pro can at $300-$400 must not be as "good" as the one with a several hundred percent markup.
If you're looking for value, look to pro gear that's made a crossover to cult audiophile status. You typically get the benefits of heavier construction, years of parts availability, accurate sound, and a much more reasonable price. That, and popular DIY projects are good value. The "many eyeballs" adage is true. Flaws will be stamped out by the geeks (and I mean "geek" in the best possible way) and you can source parts at market value, without the ego-stroking markups. $500 in parts in a DIY amp is usually looked down upon by those with $500 of parts in a $3,000 amp. Don't buy it. Learn how to cost gear yourself and then decide if it's worth paying for.
