How did Cruz get such a good campaign?

[Mehmentum]

Ultimately, much of the campaign rests on the candidate.  Bush and Rubio's failures had nothing to do with their campaign organization, and everything to do with the candidates themselves.

What Cruz has done is hook up the Huckabee-Santorum evangelical coalition with tea party grassroots fundraising.  Carson has excellent fundraising as well, but like with Bush, all the money in the world can't save a poor candidate. 

Huckabee and Santorum had horrible fundraising and therefore nonexistent infrastructure.  Cruz has been able to keep pace with and/or outraise the establishment donor networks, and has a voter coalition that could challenge the establishment coalition.  It was a very smart strategy, but unfortunately for him Trump decided to crash the party.