When the Vedas are said to have no end, how can one talk of there being an "end to the Vedas (Vedanta)"? The mesage of the Vedas, the truths proclaimed by them, the teachings with respect to self-realisation occur in the concluding part (Upanisads) of each of the Vedas, that is Vedanta.
Why should the Vedas, which are infinite have been divided into so many sakhas or recensions? A man must be imparted all that is necessary to purify his mind and prepare him for Self-realisation. For this purpose he needs hymns, mantras, employed in the performance of sacrifices and other works; he has to examine the principles behind the sacrifices; and, finally, he has to inquire into the Paramatman adopting the meditative practice called nididhyasana so as to make the Ultimate Truth an inner experience. It is not necessary for him to learn all the countless Vedas; in any case it would be an impossible task. You remember the story I told you of the great sage Bharadvaja who could go only three steps up the Vedic mountain. What a man needs to learn to refine himself, become free from all impurities and finally mingle in the Supreme Being- the text confirming to such needs is separated from the unending Vedas to make a sakha.
A Vedic recension includes all the works relating to a Brahmin's life from birth to death. A Brahmin must memorise the mantras of the Samhita, perform sacrifices according to the Brahmanas to the chanting of the mantras, and later cross the bridge constituted by the Aranyaka, the bridge that connects the outward with the inward, that is study intensely the Upanisads that are concerned exclusively with the inward. In this way he finally becomes liberated, with the inward and the outward becoming one.
For the wise and the mature a single mantra is enough to free them from worldly existence. But to become pure an ordinary man needs to perform many works and conduct worship in many ways. He has to do japa and meditation. Each sakha contains mantras, rituals and instruction in the science of the Self to enable him to find release.
(See Chapter 38 of this part entitled "Sakhas now studied". )
For a general background, please see here