I agree with this general observation for what is going on right now.  It very accurately explains why Bitcoin is worth so much per coin and every single PoS coin is worth very little.  But in the long game, I think the cost of maintaining the PoW system (because it requires so much work) will start to tax the system (especially when the subsidies expire).  Where as with a different proof-of-x system in the long game, it will be cheaper to maintain the system, thus making the coins ultimately more valuable.  

Both provide essentially the same utility, but one has hire taxes.

This of course would assume that all things being equal.  When in fact they are not.  Right now Bitcoin has a huge first mover advantage and a better marketing advantage.  Those alone might make it very difficult to disrupt even if a different platform is technically superior.