According to Osho, an autobiography is an ego-graphy; once the soul is known the 'I' dissolves, facts lose meaning, and the page becomes blank. The realized cannot compress the living experience into words without falsifying it, nor would telling his story help; instead he speaks only to lead seekers to their own realization, which alone convinces.
He won’t write his life story because awakening erases the ‘me’ and words can’t hold it—better to help you awaken yourself.