As I said, that is not likely. If a bunch of pool hoopers have invested shares in a small pool in the begining of a block (they seem to do that until some point early in the block) and this pool is currently starving (left with a huge block to solve and little hashing power to do it), pool hoppers will go back to it helping finish it (as long as there's no more profitable alternatives).
The problem in your reasoning is where I added emphasis. A pool hopper can always contributed to a PPS pool. So there will always be more profitable alternatives.
And it's not accurate that "pool hoppers profit at the expense of the non-hoppers". After all, they have actually invested hashing power... they just point their hashing power to some (currently) more profitable pool... IMHO, it's the same as investing money in a more profitable stock.
Pool hoppers do profit at the expense of the non-hoppers. The more pool hoppers in a pool, the less return per-share those who feed the pool shares at a constant rate get. That is a fact.