The frontman of the Stones? Leaving that one alone.
The point of spiritual enlightenment is to give humans a “finish line.” Some people can’t be bothered with the idea of eternal growth. Or they really, really need to feel like they’ve succeeded in life. Many of the people I’ve seen that got obsessed with enlightenment latched onto the idea with little understanding of the history or religious background of the idea of enlightenment.
So few people have it because of this fundamental ignorance. Enlightenment is a goal whose bigness is matched only by its vagueness. If you study a lot of Buddhism, then you can come to an awareness of a more concrete form of the idea. But it’s not like learning how to swim or sew or speed-consume hot dogs. You’re dealing with the extremely mushy world of understanding exactly what experience is “made of.”
Enlightenment is a very Eastern concept and it’s highly likely that any conceptualizations you read are horribly constrained by the need for translation.