I don't buy a conspiracy theory either, but you can't deny the impact that the MSM has on people's awareness of candidates. An election cycle rolls around, and all of a sudden people are told that Hillary, Obama, and the 3-headed Rino represent the frontrunners. Most people get their information from the MSM, so what do you expect them to perceive as a viable candidate. I tell everyone I know to get their news somewhere else and to explore a candidate's history and positions, but everyone's too busy to listen.
Basically the most informed in the Republican Party participate in the primaries and they are supposed to be the most conservatives. Therefore no liberal media and no force on Earth including the Republican leadership will force a candidate on them.