Only in the same way that supermodels cause increases in the price of shampoo, or sports stars cause increases in the price of cars. You can still by Brand X shampoo from KMart, or a Lada off the internet, but if you're not 100% influenced by price alone you'll make your purchasing decisions using a wide variety of other factors.

That's a theory I hadn't heard before, but not one I think I subscribe too. And the reason I don't? It assumes all buyers are equal and know that theory, and that you, as a FFer, pay a premium for your travel because you're aware of the future travel benefit. But the reality is much more likely to be the opposite - as a FFer you're probably a much smarter buyer of air travel, and you'll get better airfares than Joe Public precisely because you 'know the game'. Your decision making might be about the future travel benefit but for others it might be the present benefit - like lounge access. Or some combination. Or other factors.

All FFP's really do is aim to engender (profitable) loyalty. Is it done by bribery? Harsh word, but arguably describes the concept pretty well . . .