Because the more we hear him speak , the more we learn about who he really is. He is very condescending, arrogant, Etc and we’ll not get out of the way of the voters choice. People have spoken, he doesn’t listen
On the other hand, I started having misgivings about Cruz in Iowa when his people said Ben Carson had dropped out of the race. At first, I gave him the benefit of the doubt, that maybe it was just a misunderstanding, but info that came out later shows that it was likely a calculated move. I lost lots of respect for Cruz when he blamed the violence of anti-Trump protesters in Chicago on Trump (and he has continued attacking Trump along those lines). He constantly says stuff that's not true about Trump. He's like a high school kid trying to win debate points on the smallest issues. When it looked like Trump was going to win, I was hoping Cruz would end up as VP or a Supreme Court justice, but now I just can't stand the guy.