I constantly say that it's MM more than the Honda winning all these races and championships. This year, not only does his bike have more USEABLE h.p., but he is actually smoother on it. He is the only one that makes the Honda look that easy, however.
Watching Fabio and Maverick on the Yamaha, I think MM could best either of them. He leans farther and picks up the bike faster and can brake very late. Although, MV has improved his corner exit a lot. As well as FQ is doing, I don't believe he is another Marquez. If FQ is battling him on the last corner, I am sure if they swapped bikes, MM would be right there, too.
A couple of years ago, Marquez rode the Honda very much like you see Dovi and company ride the Ducati, so I don't think he would suffer much if he went there, either.
I don't understand the Suzuki, since Rins has two wins, but is usually an also ran as the season has worn on. I am uncertain how much MM would have to change to ride it.
He might not have a season like this one, but I am confident he would still be battling for the championship on any reasonably competent bike.