re: A Huge Portion Of Registered Voters Don't Vote
As I pointed out, likely voter polls can exclude up to 75% of the voters in a state. Because they depends heavily on what questions the pollster uses to determine "likely" in the poll. This is very subjective and can invalid the poll pretty much. There are mathematical ways to compensated for how many people will actually vote in a registered voters poll and if used correctly make for a much more correct guess.
But, be my guest exclude registered voter polls from your thinking...just don't be surprised when reality hits you.