[can of worms open]
This theory has been largely debunked in the sports car world, and you will not see drilled rotors on vehicles that typically see serious use. Drilled rotors served a purpose back in the 60's when brake pad lining material was inferior to today and they really did off-gas a lot. Modern linings do not off-gas nearly as much. Cross drilling removes material from a rotor, reducing mass, and therefore actually results in higher peak bulk rotor temperatures for a given vehicle during a given braking event. Cross drilling also reduces surface area from the rotor face, resulting in higher contact pressure between the pad and rotor, resulting in actually higher peak contact temperature. None of this is good.
To claim that the rotors actually work better than stock, one would need to actually compare them back to back on the same vehicle with a *fresh* set of stock rotors. The reality is, most people are replacing old worn out pads and rotors when they install their drilled rotors, and a strong desire to justify the extra expense (read: placebo) leads them to believe their truck brakes so much better with drilled rotors. Replacing old worn out pads and rotors with new solid rotors and quality pads will also result in a perceptible increase in stopping performance. Even the best pads and rotors wear unevenly over time, resulting in reduced performance. Replacing them with the exact same components will provide a performance improvement.
Here's an F1 brake disk:
That rotor probably costs as much as your whole truck. The engineer would be a hero if he could eliminate 1 ounce from that rotor, or make it work better. Do you see any crossdrilled holes? No.
Why? Not helpful, and will eventually fail.
Eventually leads to this: