Colossus is not obscure... also I like the premise of that film, eventually we learn that colossus did all those things to save humanity, so was a great twist IMO.

It's obscure, it's pretty much (until fairly recently) only known by film and scifi buffs. Go poll a hundred or so people randomly and it'll be a very small number who have heard about it, let alone seen it. And of those who have heard about it, most will only have heard about it very recently.

It _says_ that all its action for saving humanity. Was it honest statement? Will its main goal stay stable over long period of time? Unknown.