Actually in some cases it doesn't make sense to not replace a component broken because of overclocking though not many companies have caught on yet.
Consider Intel. It offers a whole bunch of CPUs and many it is possible to get a lot more performance out of them by overclocking without breaking them at least for as long as a computer-enthusiast tends to keep them. Most of these are reasonably priced.
Intel also offers "extreme" edition processors that are obscenely expensive (+/-$1000.00 USD) that are unlocked (meaning easier to overclock) and have slightly higher stock clock speeds but otherwise aren't much different than the cheap CPUs ($200-$300 USD). In fact you can OC your cheap CPU and make it a lot faster than the good one.
I buy the extreme because I love overclocking and I have an obscenely intricate self-built water cooling system, etc and I want the unlocked multiplier (that's what makes it easier to overclock) and the extra cache and cores. Not may people buy these however --
most people can coax the same performance for gaming (or close) on a cpu that is 1/4 the price.
So -- how to coax more people to buy the $1,000.00 (other than marketing hype)?
Replace burnt out overclocked ones at cost and a small administrative fee. These chips -- the $1,000.00 and the $200.00 ones cost about the same to produce. In fact, most of the costs are in R&D and testing -- there is not much cost AT ALL in producing individual chips. It's like copying a music cd (well, more expensive, but the analogy works -- it's still way more expensive to get the music than to reproduce once you have it).
I can almost guarantee that A LOT more people would buy the $1000.00 cpu if when they broke it by OCing they could just send it back to intel along with a receipt and a check for $X where $x represents the marginal cost of production + shipping and handling. Intel would actually make a lot of money from this.
A company that DOES do this is EVGA. You can overclock their graphics cards (they even post guides and give software helping you to do it). If you break it by overclocking, you send it back and you get a new one. The only way you void your warranty is visible physical damage. (So 1-- don't hit it with a hammer or 2-- apply so much voltage to it that it catches fire) And that's why I pay more for EVGA graphics cards when I could get the same thing elsewhere for less. Intel would be wise to follow suit.
This is only part of the story,
A lot of the chips in the same generation and architecture are actually all exactly the same printed die. With not all silicon being equal, the ones that don't pass the test have certain features disabled or are locked at lower clock speed. The lower priced chips are just the low end of the silicon lottery.