they may get there. one thing at a time. remember, only 2 years ago main events that weren't title shots were 3 rounds too.
in my humble opinion, there seems to be a lot that goes into the decision of 3 or 5 rounds than meets the average fans' eyes. i remember when Hendo v Machida was signed as a 3 rounder, before they even had a main event. i wondered right then wtf was going on. later, a month or so later, they gave the main event to Ronda. when people complained i thought, wait a fucking minute, they decided LONG AGO (at least a month ago) that Hendo v Machida wouldnn't be main event, regardless of Ronda.