What he said was not many players in Barkley's age bracket can compare to him in terms of stats. I just named 3 off the top of my head that have been statistically better than him.
Yeah and all three of those players are regarded as three of the best in the league and worth ridiculous money. "Not many" is a truthful statement - Barkley is currently in the tier below that elite, but that makes him a very good player - and that's before you consider his potential. Isn't it notable that you can only really name elite players doing better than him when the consensus is that he's been "disappointing"?
If we sold Barkley, we'd regret it immensely - no doubt in my mind. He's the type of player you build a team around; not many of those types of player exist.