Even if GSP isn't the GOAT I don't see how anyone can debate that he doesn't at least have the GOAT career. He fought in 2-3 different eras of MMA, only lost twice, avenged both losses by stoppage, held belts in different weight classes, and in his final fight after years off he came back and made an effort be exciting because he knew it was a criticism against him. He also left on top and on his own terms.Not more desperate than GSP haters pushing every false narrative they can so they can somehow decrease his greatness , So sad that they havent got over the fact that GSP is the greatest of all time yet .
Not to mention the guy really did help make MMA a little more professional and mainstream accessible. I'm pretty sure he was the first guy wearing suits to press conferences, being (almost overly) polite in interviews leading up to fights, and then he helped pioneer some popular techniques and strategies.
I was a huge fan early on and his fight against Frank Trigg is still one of my favorite all time one-sided beatdowns in MMA history. For a long time though in his prime I found him more boring to watch and I thought he was too risk averse but I always impressed by his performances.