It only works when certain fighters do it. And by certain, I mean two. There's literally only two good trash talkers. The rest are just unintelligent thugs talking trash, your run of the mill high school trash talk.
Think about it, the reason why Cruz and Conor's trash talk apparently works, and resonates with people (even though I hate them), is literally because of their intelligence, and their linguistic dexterity. That's pretty much it. When you have a stupid thug yelling, and then you have someone who has a vast vocabulary (and has a mean streak to USE those words, those sentence structures, verbally setting traps, etc), then you've got a complete mismatch and one person is getting verbally eviscerated.
Unfortunately, as much I hate to see it, this is why Dillashaw was made to look stupid as all fucking hell in those head to head interviews. Cody as well. Oh, and Faber in the lead up to their latest fight. The shit Dom was hitting him with had Faber just sitting there with those perfectly circular eyes wide open.
Look how easily Conor handled Nate at the press conference. You can say Nate just didn't give a fuck, and wasn't going to engage in it, but....he clearly did, and tried to. He just literally didn't have the verbal arsenal that Conor had. He literally lacks the words and the knowledge in knowing how to string together those words. He's a basic talker. Which, 90% of Americans are. Whole 'nother story.
Bottom line: A less intelligent person's trash talk will NEVER be on the level of a person with better IQ and vocabulary who has a mean streak in them to use it (I keep mentioning this, because it doesn't work if you don't have this darkness in you; Stephen Hawking or Bill Gates aren't going to be good trash talkers....they'd come across whiny and wimpy).