Most Texans did not vote for Cruz. He didn’t get 50%.
Just like most Republicans don’t vote for Trump in any state he wins. He’s winning with a plurality and his scorched earth Democrat style attacks on his rivals is not just growing but cementing the Republican under vote that will not vote for him in the general.
Yet Trump only won about five Texas counties. It is hard for the weak-minded to resist the celebrity and media frenzy surrounding Trump. Cruz prevailed despite this.
This election cycle is not comparable to others.