The Criteria Stuff on Netflix?

I always wondered how long it takes movies to be put on Netflix after they're released, and how come they have shows and movies from certain time periods but not other shows from the same period. I mean c'mon, if you can have a silent film on netflix, how come gargoyles isn't on netflix? They show you what you're searching for, but no, if you want to watch Goliath n Bronx n all them, nope, sorry, can't do it...... lol