Well said.
He appeared distant and formal. Trump poked fun at his Shakespearean speaking style, but there is some truth to that. He came across as a "great orator" buy not connected to the audience. He wasn't inspiring, and he wasn't a regular guy. What else is there?
While the holier-than-thou campaign themes certainly work with some voters, they alienate many more. His surrogates' rhetoric certainly didn't help. "Anointed" and "fasting" and "embodiment of prophesy" and such turned off half of his core base of supporters. Glenn Beck's ass-hattery did not help. In the age of the internet, people in Maryland know what you say in Utah.
The biggest problem: He didn't recognize the Trump threat until it was too late. Trump recognized the threat that Jeb Bush posed to a Trump candidacy, and he set about immediately destroying him mercilessly. Cruz had to know that he and Trump were "in the same lane" more or less, and eventually the bear would get around to eating him if he didn't strike first.