Emotion in Photography

Recently, my cousin was asked to make some art for the dressing room of Courtney Vance while he co-stars in a Broadway play, Lucky Guy.  My cousin wanted to make scratchboards portraits of older, more detailed faces with a melancholy theme throughout the pieces.  In order to be as accurate as possible, he wanted photographs to refer to, but not just any photograph that can be found online.  He wanted to use some of mine.  We ended up going to the city on Saint Patrick's Day to walk around and see if we could find any interesting subjects.  We found many, but none as interesting as a disable veteran (it appeared) we spotted near a phone booth.  The guy had one leg, an eye patch, one hand in his pants, and was in a wheelchair dead asleep at 1 PM.  People walked by glancing at him without fixating their attention on him.  I, myself, wouldn't have given him much though had I not been photographing (but when does that ever occur?)  

This got me to thinking...  Most art photographers I learn about in my classes have a theme, something cohesive throughout that makes a series what it is.  Some photographers have so many photos in a series, that we may never even come across some of them.  There are not many famous, successful photographers who have singular standout photos of several different things, though.   Why does the art world force us to stick to one style?  Artists are constantly advised to stand out and be different in order to get noticed, but if you're always doing the same thing, are you really being different?  One single portrait can provoke as much emotion as an entire series, in my opinion.  Bruce Davidson's Subway series is one that stands out to me.  It's a wonderfully put together work, but each photo itself doesn't bring about as much emotion to me as, say Richard Drew's The Falling Man.

It's a struggle that I hope I someday will be able to overcome: to be able to photograph whatever I'd like to without having to limit myself to a particular style or form and still invoke the viewer's thought and feeling.  Just food for though for now I guess.

To summarize, my question is this: If I were a famous landscape photographer who made a living showing beautiful scenes, but I captured the following photo, would it fall to the wayside and never surface the way my less important and impactful work did?  Here's the man who brought up this thought: