That's incorrect. In fact, they must provide the original system if available. It would be illegal to keep the original system disc without the system with which it shipped.
So if i lose/misplace/lost in fire/flood/hurricane my OSX cd(s) and then decide to sell my Apple computer without going to reaplace the originals I am breaking the law?
Anyway, the purchaser of the system can trot on down to any store that sells OSX and buy a the latest version if they want, clean the harddrive and have a fresh install.
Apple would look awfully stupid in such a court case.