How can you say for sure that Sete, Max, Barros etc were all bad racers?
How can you even compare them? Different Bikes, different tires, etc...
Sure Rossi blitzed them all, but was that because they were bad riders? Or was Rossi that good?
Think about the changes that went on between 1999 and 2004, Tires, Motors, Teams, electronics...All of them changed SO MUCH in a very short amount of time.
Guys like Barros, Biaggi etc all started their careers focusing on learning how to ride a fire breathing 500 two stroke, then all of a sudden they had to relearn and taylor their riding to a 1000cc four stroke.
No, the riders who were competing against Rossi were not bad riders or any less talented than the current crop. Rossi was just the MM of the early 2000s.
What makes Rossi the GOAT, is more than just him being a great rider, his ability to develop a motorcycle, and his PR ability is unrivaled. THAT is what makes him the greatest of all time.