This is a bit of revisionist history, IMO. While Silva was doing some damage with the leg kicks, Weidman was outstriking him with the hands, and had a very, very slight reach advantage over Silva. Between using that advantage through an extremely disciplined approach and mixing in the wrestling, he was controlling the fight, very easily won the first round and roughed up Silva a bit on the ground, which Silva has traditionally not liked (vs Henderson, Sonnen).
Did Weidman have the gas to last five, or even a couple more? Not sure, but Silva "showboating" or "clowning" was to try and get Weidman to discard that discipline that served him so well, and Weidman wasn't biting on it. So he kept trying to draw Weidman in and got caught doing so.
He wasn't showing off, he was frustrated by Weidman's success and was trying to change that dynamic.