They want to kill $XIV and $SVXY due to the higher returns paid since they started vs the crumbs you get using other products.

Hi Seth, I am glad I found your valuable insights (after reading the NYT article) on trading short vol. I have a very similar approach (taking advantage of spikes in the VIX) and found your strategy underpinning mine. Shorting the $UVXY has made me quite some money (in fact it was the biggest money maker in my portfolio). However, I have switched to the $SVXY because it lets me sleep better: being long I cannot lose more than I invested and I don't have the problem that my broker wants the borrowed shares back (this has happened to me twice). Thanks! Will follow you here and on Twitter.

Okay but the phrase "like instruments" may be confusing to some. I wanted to be clear that even instruments appearing to be opposites, or at least on opposite sides such as $VXX and $XIV, $UVXY and $SVXY, $ZIV and $VXZ etc. all declined in 2015.