Yes, a missing computer is rather compelling evidence that a theft has occurred. Businesses respond with Locks, Alarms and Guards. For street level crime this makes sense. Usually, not enough. Industrial spies steal the information, not the containers.
Information is worth more.
Continuing our computer example, nothing will appear to be missing. The computer will still be on the desk. The information will still be on the disk drive. Chances of being caught stealing the information are slim. The information will be sold for what it is really worth.