(And as a side note, several of my friends who rent films rather than buy have complained that quite often the rental copy of a DVD/Blu-ray doesn't even contain all or even any of the extras, so that makes me presume that in a lot of cases rental companies get "rental only" copies from the distributors - and unless someone renting is aware of all the extras on the retail copies, they may not even be aware that what they'd gotten was a "rental only" copy.)
Now, don't forget people, that even though this film played in theaters for almost half a year, made hundreds-of-millions of dollars, and is outselling in droves other DVD's, it's a "flop."