Windows Drivers (.sys) packing/protection

I agree with Cobi on this one. Generally most drivers are created for redistrobution. If you want your device to work most of the time you don't want to invest the money in stopping other people from decompiling it.
For the hardware that really needs the protection, then generally I'd think you wouldn't be able to normally get your hands on it. Also, whybother care if people decompiles it? Most of the time people optimize the drivers and leave it opensource. The dev goes and steals the code. It's helping them in the end.