You realize that only works if someone has PHYSICAL access to the device with the cold storage? With physical access, it's easier for a thief to steal the wallet file, regardless if it had internet or not.
Cracking the password to the wallet is another story.
Right. If a hacker had physical access then they might as well make a copy of the hard drive and/or outright steal your computer in an attempt to steal your wallet files. This would make more sense then going through the hassle of taking data wirelessly as I would imagine that many people would tend to have somewhat easy to crack passwords on computers that hold cold storage wallets