Another factor : suppose you fry your 980x through heavy overclocking. You paid $1000 for the chip, and at least $900 of that money went straight to Intel. Intel sold the chip with an unlocked multiplier, so clearly they intended for you to play with pushing the specs on it.
Anyways, morally, what harm do you cause Intel if you do abuse the RMA? Manufacturing a new 6 core processor and mailing it to you probably costs Intel less than $200. Thus in this example Intel still makes tons of profit on the deal.
Now, part of the cost is that a processor represents Intellectual property : when you buy one you are buying a "license" to that IP. But if you turn in your old chip and they send you a new one, you still only have 1 license.
I would suspect that i7s fall in a similar area. I doubt it costs Intel more than $100 to manufacture a single i7 chip.
And, come to think of it, for this particular example we need to talk about marginal costs. The marginal cost of an i7 or a 980x is probably less than $50. (aka the costs of making just one more chip, which means you can ignore the costs of the fab equipment for the purpose of this comparison)
Technically speaking even if you were to abuse the heck out of the RMA process all day, and lots of people were doing this, it still wouldn't raise the costs that others pay for processors. Your actions would have the effect of lowering Intel's monopoly rents.
Anyways this kind of thing is self-limiting. You won't get much of a performance boost by overvolting to 1.5 volts +, and you'll lose any time you saved by having the RMA the darn chip every few months.
Intel is going to start charging all of us a price premium for unlocked CPUs, with OCing impossible without paying that. Once they do that, I think this argument will change to "overclock it all you want, and if it fails get a fresh one from Intel"