getting in a bit late, here - but I think its mostly because the vast majority of americans don't have a clue about history and can only remember the past 20-25 years. Every contest like this ends up heavily weighted towards those people who the voters remember clearly. Look at baseball polls on the greatest players. The top vote-getters typically are the modern-day players with a few historical players people can remember thrown in. People have very short-term memories in general...
Personally, I think its ridiculous that RWR won. Not to say necessarily he shouldn't have been in the list or among the finalists, but the "greatest"?
Should have gone to Franklin, IMHO. Is there anything he didn't do? He invented the lightning rod, Franklin stove, bifocals (and many other inventions). He co-founded the 1st hospital in the US. He helped introduced several crops to the US. He started the first fire insurance company (mutual). He helped found two colleges. He was the first postmaster, started the 1st circulating library, was a noted journalist and philosopher, started the 1st police department and 1st fire department in the US, invented a musical instrument, was an ambassador, governor, and colonel in the militia, fought for lighting, cleaning and paving of streets, ran several businessses, and the list goes on.
Oh, and did I mention he wrote parts of the Declaration of Independence and the Constitution? That and he got the very much needed assistance from France. Oh, and he was the only person to sign the DoI, the Constitution, the Treaty of Alliance with France, AND the peace treaty ending the revolution.
That and (in contrast to many of his contemporaries - not to demean them) he fought for the abolition of slavery and for native americans rights.
Seems to me thats an incredible list of accomplishments (yet he never seemed to be power-hungry, either)... Sorry, but IMHO Reagan couldn't hold a candle to Franklin...
Agree on every point and can add a few of my own!