Hopping proportional pools and exploiting their resources is a natural step in the evolution process of bitcoin pools.
Large proportional pools have been on the decline for ages & will eventually die out completely once the core miners realize they are working for someone else;
They are paying out of their own pocket so that somebody else may profit.
I think Inaba on page 2, the master of Eclipse pool, has put it eloquently in the last sentence:
Those poor miners making up the 150 GH/s are getting raped like a two bit whore.
Of course, those 101+% pools will disappear too, but only once the proportional model disappears first. Right now, non-hopping, perpetual proportional miners are the suckers of the system, the prey. Through either lack of knowledge or sheer ignorance, they distort the balance of pools so as to create an incentive for predators.
True equality in mining rewards will exist, but only when these miners finally understand they are damaging their own earnings.
(This model relies on the rational assumption miners' main motive is profit;
It does not take in account irrational motives such as supporting a pool for ideological reasons, or wanting to give free money to pool hoppers out of generosity etc., so it is still possible there could be proportional miners 3-5 years down the road)