While I certainly agree with you about the homogenization of society, I don't think this is entirely correct (and I disagree with your characterizations of Washington and Franklin).
Why don't you think it is correct? I have seen people describe both as such. I read a whole little article in a news mag recently where some shrink "analyzed" Franklin and said that he most likely suffered from some "High Level Autism". He said that it explained why he never kept a job for long, why he invented things, ect. This is the world we have come to, if you stand out it is because of a problem.
People have always been more tolerant of eccentricity in fiction than in real life. Fiction has always served a cathartic function.
Why is that. Better yet, it's a two part question. Why is it people are more tolerant of eccentricity in fictional charecters than in real life and why are so many fictional charecters eccentric.
I think it's because we read, watch, and experience fictional charecters on an individual, personal defined level. We experience people within the context of society and it's defined level. This leads to descriptions like "he's a great person, but..." We can accept these people on an individual personal level, but when we have to identify them based on the social defined points that our society demands it falls apart. It's why the "nerd" and the "jock" have to pretend not to be friends, or why we even have definers like nerd, jock, geek, goth, prep... Society has taken over, rather than us controlling society.
As to why so many fictional charecters are so, I think it is because the field of "fiction" (books, tv, movies, ect) is one of the last which truly accepts and even promotes the really eccentric individuals in real life within it's ranks, and they end up channeling themselves and people they have met into their works.
That is why fiction provides a cathartic function, it allows us an escape form our society, from our social collective group think we must all follow for fear of being shunned by the rest of the members for "being different". We hide behind our walls and escape into fiction. We hide within our heads in the world of fantasy. We do this because the real world has become an oppressive socially dictated collective mindset of rules we are forced to follow because of our own fear of rejection from the very society we grow to hate with each passing oppressive day.
Hell, look at when people talk about star trek. When people say "it's a great future to work toward". Why is that, well they always answer, "it's because it's a world where people are accepted for who you are. Where it doesn't matter what you look like, where you came from, how you talk, all are accepted for who they are with out judgment." Roddenberry was an eccentric, he saw how the society was turning against the eccentrics. This was why I think he saw the ultimate "bad guys" trek as those which controlled people. The famous Kirk's "Your God is a lie!" moments. The loss of individual control to the collective of the Borg in TNG... Star Trek under GR was always about promotion of the individual over the collective.