Even with a win Nick doesn't have the chance to be considered the best of all time.
See we could go back and forth with this. Ultimately GSP has more to lose. But not as much as Anderson does. If Anderson beats GSP he will always have teh excuse that he was the bigger man and just THE MAN. He could still go to 170 and defend his title for several more years and still be the poster boy for Canada. GSP already is going from 900-1 mill ppv buys to 700,000. And probably less vs. Hendricks unless it was a stacked card. Trying vs the best won't hurt his cred. And beating the best would push him to levels he doesn't even imagine right now.
I'd watch Diaz - Anderson and so would a lot of you. Nick annd Anderson will still make their money even if Georges doesn't want to share.
It wouldn't hurt his cred, but why bother? GSP's got it made at 170, he just beat his toughest test in Condit and who at 170 really stands a chance to beat him? Hendricks? Unlikely, Diaz? Probably not. Marquardt? It's an interesting fight but I'd still pick GSP. He has a lot of years left in his career and he could potentially tie or even break Anderson's title defense record.
If Anderson loses a fight and I think Anderson will lose soon, then Georges can still become the GOAT by never having to fight him. Look at what happened to Fedor, he lost a fight and now Anderson took his spot, if Anderson loses Georges can take his spot, and maybe in the future Jones will take Georges spot. He's young enough to eclipse all those records if he can remain champ.
I think it's a unanimous opinion, at least on this forum that if they do fight Anderson would probably beat him, I know many feel that way and I do as well, but if I'm GSP, why bother? All it takes for him to move up on that list of 'Greatest of all time' is to keep doing what he's doing and for Anderson to finally lose, and Georges is much more complete than Anderson so the chances of Anderson losing before he does is more likely.