No Call of Duty World at War Download in the Playstation 3 Store? Wtf?

Ok I thought that Call of duty 5 (World at war) was down loadable and you can download the whole game. but it isn't on there??? wtf?! I don't want to go to the store and buy it. can someone tell me why it is not down loadable

Suggestion:

you cant download it online because the games too big and would take up too much hard drive space also lots of people would games share (go on someone elses account and download it for free) and stuff like that.