That's because it can't be broken. You can't break what isn't there. Pre-load only downloads 99% of the game. Let the user download the game sans a few important bits, say the entire executable, and upon release enable download for the last tiny bit. Most retail games release weeks early because it's impossible to stop once the disc hits manufacturing.

Retail discs that require one-time Steam activation can be uncrackable because those important bits aren't on the physical disc. Once a Steam game is unlocked for play it's immediately cracked and released into the wild.