“The Greatest Showman” plays like the Disneyland show of P.T. Barnum’s life. It’s the version he would’ve told. That’s fine. It didn’t have to be a musical expose into Barnum and the institution of the circus. Jackman and company set out to give families a rollicking good time around the holidays and they will surely accomplish that goal. If they had tried a little harder they could’ve created an experience people won’t forget two hours after they had seen it.