Very few music stars live to 90, Guyver. It's the alcohol abuse that gets 'em mostly. I know what you're saying but it's about cultural impact and popularity more than number of albums. Nirvana only did 3 studio albums but their influence and impact was massive. Back to Black was the biggest album of its year and an international hit.
not trying to offend anyone with the comparison, it's just the first one that popped to mind.