Its not overworking them, its working in the voltage powerband of the motor. Look at it like a 2 stroke engine, you got to find the right pipe to run efficient. Brushless don't just all run on 7v and we over run it, Motors are built for a particular voltage in mind. My lehner basic xl 1200, runs 1200kv (rpm/v) its rated for 50,000 rpm's (I think), I am running it at 22,200 RPM's, I am not overdriving it. Now if i were to do say, 12s lipo (44.4v), thats a different story. Thats 53,280 RPM's, and thats overdriving that motor. Right now, I'm at less than half the rated max RPM of this motor.
Like said above, Not all of us running high voltage are going after Nic Case (though it would be fun) , Most of us are trying to lower the cost of electric RC. With low Voltage the electronics have to work, With high Voltage and proper gearing, electronics are cooler and used less and therefore last longer. Look at the guys that can pass 1,000,000 volts through their bodies, they can do it because the voltage is not the killer, the amperage is. They do it at 3 to 5 mA, lets crank it up to 100 amps and see what happens, they'd cook. same goes for your electronics