I think you've got an incorrect recollection of history. Not saying Fifita will be as good a player but Taumalolo was still in and out of 1st grade until 2014 when he was 21 and didn't make his debut for NZ till then. Fifita has been a 1st grade regular since he made his debut at 18 and made origin at 19. Honestly the only young forward I can remember with a similar career timeline was sonny bill
Taumololo was just as rampaging as fifita was out wide at the same age.
Fifita has played about 5 amazing 15 minute spells and maybe 10 other games across his 37 first grade games so far. He has had just as many games where he has been invisible.
Taumololo was held accountable for those invisible games early in his career. Cowboys were contenders every year. Broncos don't quite have that, fifita is immune to being dropped because no one else is there.
We literally had Hess and Chricton doing what Fifita is doing just a few years ago. Dave taylor in his last year at the broncos. T-rex during manly's 2011 premiership. Even Cartwright, while being a different style of player, was hyped up as the big revolution in 2nd rowers in 2016. Sam Burgess came in a force of nature into the souths side after impressing for GB im 2009, it wasn't until 2014 that he achieved consistency.
Getting hyped by sporadic glimpses of Dominance in a young 2nd rower is frought with danger.