Why is Nas not rated among the top richest rappers?

sales is not his first priority ..... best lyricist alive. all rapper rated in top 20 richest rappers are not good when it come to real lyricist if u know hiphop, best rapper of all times is 2pac,nas,krs one,guru and biggie small, so best group rap of all times is wutang clan,bootcamp click and bone thugz and harmony. best producers of all times is dj premier, pete rock, j dilla, madlib and 9th wonder