I completely disagree. EVERYONE on this planet knows who Vito Corleone is. Can't say the same for those other characters.
In fact Colonal Kurtz is probably more well known than those characters.
By the way I mean just people in general, not people who are into movies.
I think you VASTLY underestimate the popularity of ON THE WATERFRONT. It's an American classic. And people certainly know both quotes as they've been recycled countless times for clips and parody. Maybe the generation that considers everything before 1970 old and obscure wouldn't get them, but the aging Baby Boomer demographic certainly knows both films.