On top of this, air cooling has come a long way as well. With a decent air cooler you can cool as much as a bad Watercooler and with a good air cooler you can be on par with all but the best watercooling systems. This goes back to the parts running cooler than they used to partially, but still, expensive watercooling is no longer needed for mild-to-mid OCing, especially since the chips and MoBos are designed for it.
That said, I still am not talking about a 5gHz OC here, just a mild 4.0-4.2 OC. I think even the stock coolers can handle up to 3.8-4.0, though it is not generally recommended. A cheap $30 cooloer like the Hyper 212 EVO can allow you to OC it easily. Also, due to the chipsets on the Z77 MoBos, it is a lot easier than you think. Open BIOS, change a setting, done. It is unlocked and designed to do that.\
Now all that said, I am still not a huge fan of OCing, though am probably going to do it myself on my next upgrade that I will be getting soon-ish. It just seems to me if they are designed to run that way, why don't they just sell them running that way. However, a lot of that does not have to do with the chip but instead the MoBo, so they can't really do it in house.