"If skills sold, truth be told, I'd probably be, lyrically, Talib Kweli." Jay-Z's lyric makes nominal sense, at best—not that Kweli wasn't a skilled rapper, but Jay was always a more dexterous one, even when he "dumbed down" to double his dollars.
But in a larger sense, this statement points to why "skills" are such a bizarrely irrelevant factor in 99% of conversations about hip-hop. For most critics, the term "skills" applies to a very narrow range of possible talents. Songwriting, charisma, the possibility of surprise—anything that describes a well-rounded artist, or results in an enjoyable piece of music—are all subservient to the rapper's technique.
If there's one dominant thing in the rapper's control, it's their personality. Personality is, admittedly, more abstract, but that's what has made the biggest impact for every classic rapper.
Jay-Z isn't just dope because he's skilled. He's dope because those skills help form a better picture of a nonchalant rap star, whose nonchalance perfectly conveys his jaded persona. Skills are only a means to an end.