It depends on the artist, but theres an obvious trend away from groups to solo artists. Its a shame because you miss key dynamics that were present in a lot of classic Hip Hop. Which is - steel sharpens steel, natural chemistry, less self indulgence etc.
As others have said, it seems like a much better starting point than trying to go it alone, even from a business perspective. Wouldn't it be easier for a label/manager/artist to promote one group than 3 or 4 solo rappers? By the time you get to the solo album, the fans are already anticipating it. The artists can still go back to the group because theres a foundation.