> Correct me if I'm wrong, but most of these brands are riding on their brand equity, not the superior quality of their apparel.

I think you're wrong in terms of disruption. The people who go by brand equity, in my opinion, are the uninformed consumer. This tends to be the 30 year old+ demographic, people who don't know how to exploit the internet. On the other hand, you have 20 year olds and younger that are extremely informed due to familiarity with internet discussions. The rate of information is incredibly fast in this case, and word of mouth can be a powerful thing. And this group is only getting larger and getting more buying power.

In fact, there's been a large rise in direct-to-consumer apparel retailers, and by all accounts they are doing very well. Take a look at Everlane for example.