I don't know if you're old enough to remember a motorcycle racing phenom named Freddie Spencer. First and only guy to win 250cc and 500cc championships in same year, youngest ever MotoGP champion - beat the tar out of King Kenny Roberts, the acknowledged GOAT of the time... Sound familiar?
Turns out he burned out fairly quickly for many reasons and even though he is fondly remembered, his reputation is no Agostini or Roberts.
Marquez has a long way to go before he approaches Rossi's legacy, and even then he would have never won on two-strokes, 4-strokes with no electronics, and in as many classes. He's on a fantastic start with tremendous potential, but ultimately history will be the judge.
I'm in agreement with Rossi's statements that Dorna has done a pretty good job, actually. The battles at this race were far better than previous years where the "aliens" were in their own class. Hopefully it remains that way for the rest of the season.
Sometimes the candle that burns the brightest...