THERE IS NO MOON. (Destiny)

by stabbim , Des Moines, IA, USA, Friday, July 18, 2014, 08:25 (3792 days ago) @ someotherguy

Your math is ok but your logic isn't. 1/5 file size would only mean 1/5 the game length if every single mission, event, and moment was composed of 100% unique files. Textures, character models, etc. are re-used a lot. The part of the file size that defines missions and such is probably a tiny piece.

tl;dr, adding a LOT of missions and other such content probably doesn't require as much extra space as you're thinking it does. There is no way you've actually seen 1/5 of Destiny at this point.