All this "prime" business is pretty irrelevant in my opinion. He's riding a motorcycle ffs, not pedalling a pushbike or running or swimming. Yes a MotoGP rider needs a certain level of fitness, but experience can be as much of a leveller in this sport.
This day and age, modern diets, fitness routines and vitamin supplements can add decades to a rider's effective career. There's nothing that special about Rossi being competitive at his age, if he was riding his ass off on an uncompetitive bike then yes, but he's been on one of the four best bikes in the world for most of his career. The two that he wasn't, well we know how that went...
As has been mentioned, Rossi has come up against faster riders and will soon use his "age get out pass" as an excuse to leave the sport whilst still proclaiming he's the goat.
tps7c has had lots of honest and very valid statements proving Rossi's advantages, his nasty and dishonest behaviour and the general ugliness he rings to the sport, and whilst he claims to take them under consideration he steps around them like fresh dog turds on a sidewalk. He's a bopper of the highest order who will continue to pedal his rubbish theories because he truly and desperately needs them to be true. He's already started to get personal and will only get worse as people refute his claims. Mark my words, this bopper will get more and more irate as his theories are shot down...
Best ignored.