1
Conor McGregor Conor. Too much reach, speed and power. KO within 3
2
Tony Ferguson Tony. Too big, well-rounded, durable, reach. UD or late finish
3
Dustin Poirier BJ wins. Too skilled for Dustin
4
Eddie Alvarez 50/50 Eddie is pretty fucking big and is well rounded.
5
Kevin Lee Kevin. Kevin is too big, strong, well-rounded and has a huge reach
6
Edson Barboza Barboza. Speed and striking difference is too much
7
Justin Gaethje Gaethje. Too big, wrestling is too good, too durable
8
Anthony Pettis BJ wins. Too skilled, size differential will not be enough to negate that
9
Al Iaquinta BJ wins. Better fighter everywhere
10
Nate Diaz 50/50 BJ is a better fighter but Nate's big and durable
11
Michael Chiesa BJ wins. Chiesa is big but not skilled enough to hang with him.
12
James Vick BJ wins. Huge size disadvantage but not enough to overcome skill disparity.
13
Alexander Hernandez I honestly don't know who this is. Not even kidding.
14
Dan Hooker BJ wins. Dan is massive and has the reach but BJ is too skilled for him.
15
Islam Makhachev I don't know who this is. Have heard of him and seen him fight but can't recall anything about his fights.
Too long didn't read. BJ beats Poirier, Pettis, Iaquinta, Chiesa, Vick and Hooker. 50/50 fights are Alvarez and Diaz, everyone else beats him because they're too big as well as being skilled fighters.
In summation: The current era of Lightweight MMA has much larger fighters who are equal or more skilled than BJ's contemporaries. MMA athletes have evolved and the game has passed him by. It's sad to say but it's a fact of life in all athletic endeavours.