I can rap, pretty damn good, but that don't mean I can make a statement to say I could outsell Drake if I wanted too. Not knocking your skills. But if you were that good you would be in the league, but your not in the league. Rather by choice or lack of the talent you think you have, your not playing anywhere near the capacity that he is, nor are you playing against the comp that he is.
A brawler could say he would knock out Mike Tyson if they fought, but Mike fought heavyweights, and the brawler only fought local street dudes. Who do you think would really win?