Why doesn't our attachment to life fall away despite understanding that there is nothing to be gained?

According to Osho, your attachment persists because what you call ‘understanding’ is only in the head—verbal, borrowed, momentary—like a garden’s fragrance that fades once you step out. Real understanding is existential, of the heart; it becomes your very way of living. When insight is authentic, you simply cannot live contrary to it—then clinging drops effortlessly.

We still cling because we only understand with our minds for a moment, not with our whole being, so old habits take over again.