He's made the most money, that's all that really matters to the fighters, so he is the GOAT to his fellow fighters.
Actually, when asked, most fighters won't cite money as the "thing that really matters". I wish they would - they'd all be in better spots if they did, but to your point. No. On both counts.
MMA greats (especially the ones listed here) have legacies as champions. I've said this before, but what is Conor's CHampionship Legacy? Some will say "Two division title holder", most will say "never defended a single title in any organization". THAT will be his legacy. My guess is, if nothing changes and Conor goes off to pursue other ventures, history will remember him as a strange "flash-in-the-pan". A weird anomaly that appeared quickly, did some unusual things, and dropped away just as fast.
His road through the UFC was littered with favorable match-ups, as well as being gifted the ability to pick and chose his battles. People will say "He beat Holloway", and yeah he did. It was a great performance (with a severe injury no less), but it was against a 19 year old kid with comparatively little experience. He legit beat Aldo, and this is one of the few times he lived up to his own hype. The rest of it? Not so much. Almost every other fight he was in against a smaller man (and had a considerable reach advantage) who's style was a favorable match up for him. Even his fight against Nate was engineered so that he had nothing to lose. If Conor beats Nate, "Wow! Nate is HUGE compared to Conor and he STILL beat him!", and of course if he takes an "L", "Man! Nate is so much bigger. Conor is such a warrior!". So it didn't matter. It wouldn't effect his rankings in his own division.
Poor Eddie Alvarez was already mostly used up by the time he faced Conor (too many straight up wars with Chandler before he even got to the UFC), and don't even get me started on Dennis Siver. No, Conor will likely not be remembered as a true "great" in the same sense as guys like Randy, GSP, or SIlva - I think it's more likely he'll be remembered as a more successful version of Chael - a guy who was extremely smart and careful with his career, and talked his way into a lot of money. Nothing more, noting less, but NOT an all-time great.