. . from producing trees. They think they are mature trees even when very small and will produce fruit very soon. This is done particularly since the quality and quantity of fruit from a seed sprouted tree is not at all dependable.

Of course the host root will try to take over by sending up saplings from the base which are generally cut off - though I do see decorative trees where the graft produces a large trunk and canopy and the saplings are trimmed into an attractive hedge surrounding the base.