Outsider candidates, such as Donald Trump, Ben Carson and Carly Fiorina, should be considered “big shots” due to their relatively strong poll numbers. This means media coverage has little influence on the chance they will drop out early, as long as they remain competitive in the polls and have sufficient funds. But if they do fade in the polls as the primaries begin, they will be more likely to drop out, even though they can self-fund to keep their campaigns going.
So what about Christie and Kasich? Their main problem is that it has been hard to break through and get substantial positive media coverage early in the campaign. And, similar to Perry and Walker, Christie and Kasich are career politicians who still see a future in Republican circles. Staying in too long may hurt them in the future.
On the other hand, if Christie, Kasich, and the other “career politician” candidates assume that outsiders like Trump or Carson won’t win the nomination, then perhaps it gives these candidates a reason to stick it out as long as possible — waiting for something to happen so that they can move up.