The Republican's have had a hard time winning the presidency the last two elections because the bulk of the national candidates come off as out of touch with the majority of America. Americans demand a moderate leader.
Even George W. became increasing moderate once he needed allies from the left. Actually, John McCain would have been more successful, may have even won in 2008, but campaign advisers and Republican money needed him to be less moderate to secure the die-hard right wing vote...Enter Sarah Palin, and we all saw how that worked out. But Sarah Palin, Ted Cruz, Rick Santorum, Mike Huckabee, and Donald Trump don't really want the Presidency...they want to expand their own name brand. They are compelled to campaign to advertise their brand to a national audience. However, they all know they have way more influence and earning potential on talk shows and speaking engagements...which in many cases hurts the Republican party.
Most of the people on the above poll would consider it a nightmare if elected, most are on their way to being the head lobbyist of their desired corporate entity or back to being a talking head on FOX News, and need national legitimacy to secure big money, increase segment ratings, and pad their 401K.