If we take the definition of enlightenment to be the dissolution of the self, once that happens, there is no self there for it to happen to.

If we take the definition of enlightenment to be letting go of desire, we will no longer even desire enlightenment. Therefore, if we have truly let go of the desire for englightenment, it will be meaningless to us once it happens.

If we take the definition of enlightenment to be being fine no matter what happens, it doesn't matter that enlightenment has happened.

To many definitions, enlightenent is a form of death. But like actual death, it's only a concern for those who are still alive.

If you become enlightened, Frank, you will no longer be the Frank you were before you were enlightened. Frank cannot become enlightened. Enlightenment takes the place of Frank.

Essentially, this seems to be what happened to Eckhart Tolle. He absolutely fucking hated himself so much, he disappeared. What remained was an empty shell.