All I said is that the VIX slope may not be as predictive of risk premia as the author suggests. I never said anything about the risk premia collapsing, futures representing insurance for long equity holders etc. Contango be reduced....
The paper states if the vol is inverted, you aren't being well compensated for the risk, basically. Vix slope is meant to be an indicator. That's the primary focus and it uses VIX slope as an indicator for a wide range of risk premia (not just the vol risk premium).
My claim is the VDAX slope does not have similar predictive power over vol risk premia in Europe.
VIX inversions tend to coincide with a number of other things, like vol spiking upwards, vol at high levels, changes to risk reversals, etc. Each of these is a viable signal instead of the VIX slope alone as to whether one is being adequately compensated for Vol risk.
I never made conclusions about the use of VIX instruments. I never said anything about futures representing insurance or risk premia collapsing.
Inverted vix slopes do not occur frequently and tend to indicate the market is stressed. They are typically short lived.