I was also wondering at what point (if ever) would the SC be able to be dropped and we become a "one word" city. I think you may be right krazeeboi, there are many Greenvilles in the US. Kinda like Springfield. If you are a Simpson's fan you know what I mean.
Some very small or non-descript cities do not need to be qualified by the state abbreviation. They may be defined by sports events (Augusta), sports teams (Oakland), not-so-nice events (Waco), unique names (Albuquerque), affluence (Beverly Hills), weather (Buffalo) yadda yadda yadda.
A quick Mapblast search yields Greenvilles in AL, MS, IL, NC, TX, ME, WI, OH, TN, NH, NY, RI, PA, UT, IN, MO, FL, GA, KY, DE, CA, CT, IA, LA, NJ, OR, VA, WV, NV, OK and of course SC.
I guess we would need quite a differentiation to overcome that many Greenvilles.