It's because most are now millionaires. Everyone who sold anything for bitcoin now made more than 6x just because the price of bitcoin is skyrocketing. Most vendors are fucking rich now. Also the volatility, most markets don't want to deal with it. We are seeing the end of days, boys. I haven't ordered anything in months simply because all the good markets went down.
All the vendors are not millionaires. There were plenty who were small time. You also must think that they had already begun cashing out as they were vending.
There are several things happening right now that I think have led us here. One being that it has become very apparent that Bitcoin is easy to trace. Therefore another currency must establish itself, but hasn't yet. Another is obviously there are a lot of market shut downs/shitty markets.
This is not the end. It's the end of an era. Not the end of the scene. Things just need to evolve and when they do they will move quickly.