Apparently, Ted Cruz lacks the ability to rally people to his cause. They ain't buying what he's selling. It's either the message or the messenger and judging by recent endorsements, it's likely the messenger.
Correct, Americans enjoy liberalism and being entertained.
Or people are afraid that if Cruz gets the nomination, the Dems will step up the "he's not eligible" meme and get him disqualified. They are dirty and underhanded and it's hard to take that chance.