Already posted time and time again.
Brilliant 250cc riders like Carlos Lavado, Anton Mang, Christian Sarron, Sito Pons, and others were unable to adapt to 500s. Sarron, who had a single 500cc win, was brilliant as long as his tires were fresh. In 1988, he ran up a string of five-consecutive pole positions on a Yamaha 500 and finished fourth overall behind Eddie Lawson, Wayne Gardner, and Wayne Rainey. But Roberts, then in his first year as team owner of the Lucky Strike Yamaha team of Rainey and Kevin Magee, said in an interview that year, “That 250 style can get you on the pole, but when the tires are worn, you are f____d.”
If telling things as they are is "denigrating" then you will be stocked into the fanboyz zone, if you bother looking at the moto gp records and figure the lap times, partials, lap records and poles for Lorenzo Stoner and Marquez, when Stoner had the tyres he needed and was not injured (10 gp wins, total domination), then you will stop asking question and trying to imply i'm throwing flame bates.
And don't flatter yourself, i read K.R interview and he never said ANYTHING about Jorge riding ability bar this comment he made in 1988 about other 250 styles 500 riders which happened to be mostly 250 world champions.
What he was saying was that Jorge was a fighter, not that he was an outstanding rider, he even said he was not a natural such as Rainey which says a lot, you accuse people of doing what you are doing yourself.
Not only i have done my home work previous to even signing in to this forum but i also tried these things on diverse M-C including 2 strokes and 4 strokes on tracks, the only technique i never tried was taping the rear brake to turn it, instead i used engine brake, since i never rode a 500 TZ before going to 4 strokes, i guess if you had such experience we wouldn't have this conversation in the first place because you would know what this is all about.
ps if you put 2+2 together you'll figure Roberts talking worn tyres and Massimo Meregalli saying "Jorge continued to have some difficulties, especially because of his riding style" after Sepang is exactly the same. It's lack of grip.