I hate to say it, but Clapton doesn't get his due because he lived. Had he OD'd in the early '70s like many of his peers, he would be even more famous than he is now. Instead, he overcame his addiction, lived, and continued to make music for thirty more years.
Personally, I'd put him or Hendrix above Cobain...
"Personally, I'd put him or Hendrix above Cobain..."
On a scale of one to a million, put Clapton at a million, Hendrix at 500k, and Cobain *maybe* as high as 0.0001. Maybe.