The truth of the Single Buddha Vehicle is more than simply a replacement or a merging of all the other practices of sravakas, pratyekabuddhas, and bodhisattvas. It is the faith and the practice of the Buddha being already manifest in our very lives. It isn’t about becoming something but of being that thing. We are Buddhas when we awaken to that in our own lives, which we can only do by first practicing with faith, not by reasoning.