Calipari's main value as a college coach is his ability to recruit players, which he is able to do because he makes dudes lottery picks. I think Cal feels like he failed Skal a little bit this year by not showcasing him properly. This kind of pre-draft hype job adds to Calipari's rep as a guy that gets his players into the NBA.
That being said, I'm sure he kind of believes it too. I, personally, think it is ridiculous to think that a 23 year-old would be drafted 1st overall in 2019. Look at the crap Hield and Dunn get for being 22 and they are guys most people slot into the 4-7 range.