You realize the sport evolves right? Another 15 years and the WW champion will make prime Usman look like shit.
The WW champion of tomorrow will be an upgraded version of the one of the today and the past.
You are acting like one of those people who argue Michael Jordan can beat Lebron lol.
Usman is too strong for GSP, too fast, too much stamina, better nutrition, better coaches, more collective experience, and more skilled.
Usman will make dominant GSP the way GSP dominated Hughes.
You can’t compare the fighters of yesterday to the ones today. Just like how the WW champion 15 years from now will be faster, stronger, and more skilled than Usman.