Although I have no evidence to back it up, I believe that Cruz only ran for the U.S Senate as a platform to run for President, and isn't interested in being a senator for the long haul.
Oh, you mean just like Hillary Clinton who only ran for the U.S. Senate from New York in 2000 as a platform to run for President, and wasn't interested in being a Senator for the long haul.
Where did I say that I thought he did anything wrong? A lot of politicians first run for lesser offices as a platform to run for higher office, though not normally for the U.S Senate.
I agree he probably will finish out his term once his ego fueled presidential run comes to an ignoble end, but I don't believe he will run for reelection. He's shown no interest in learning the details of legislation and is completely uninterested in the office except to be a bomb thrower.