(1) The author confuses executive experience with leadership. The problem is, we are in extraordinary times that require an out-of-the-box type of candidate who won't play by the rules set forth by the very people that candidate is trying to replace. A conventional candidate, one that gives generic platitudes to "play it safe" and accepts the premises set forth by the Left, will lose.
(2) The Internet - most importantly live, streaming, on-demand video, blogging, and social media - is today's equivalent of the political chitlin' circuit. There's no need for a candidate to spend gobs of time in office (though I agree with the author, that Carson and Fiorina are non-starters PRECISELY because they haven't been elected to anything) to "hone" his/her skills, so to speak.
(3) Well-known does not equate to being at the top of the polls. The conservative base HATES Jeb Bush's guts, him being well-known is completely irrelevant.
THIS ^^^^^^