Dan and Jake are nowhere near their peak. They are 21 year olds who only starting playing seriously at 19. Big guys like them often don't even make firstgrade till they are 23, and peak at about 28.
This year they will be the same age King was when he made firstgrade, and 2 years younger than Yates was, and 3 years younger than Fitz was - and they already have 2 years of firstgrade.
A good comparison would be Dan and Jake against a couple of middle forwards who are seen as up and comers with a big future - Herman Eseese and Mitch Barnett.
Dan and Jake were born in '96 - Herman and Mitch were born in '94.
Dan and Jake have 41 and 39 firstgrade games - Herman and Mitch have 33 and 31.
Dan and Jake have been in an NRL system for a few years - Herman and Mitch have both been in the system since they were 15 or so.
The perception is that Herman and Mitch are up and comers with big improvement in them, but they are older, smaller and have far more coaching under their belts.