Who says that the branches got reconciled and people lived without any discrepancies between branches? Actually they never got reconciled and Hindu people have always lived with discrepancies between branches just like they live today with various branches Shaiva, Shakta, Vaishnava, Saura, etc.
The purpose of Vedanta is not necessary to reconcile those ways or branches but to teach us what of all those teachings is the ultimate and correct and which is not, so that we do not stay to be an ignorant in this world as to what is the ultimate purpose of all Vedic knowledge. As Lord Krishna says in the Bhagavad-gita 15.15, a scripture which is said to be one of the pillars the Vedanta is based upon, namely prasthana trayi:
vedaiś ca sarvair aham eva vedyo vedānta-kṛd veda-vid eva cāham
By all the Vedas, I am to be known. Indeed, I am the compiler of
Vedānta, and I am the knower of the Vedas.
That's the purpose of the Vedanta, to direct us to the conclusion, to the final aim, and not necessary to reconcile branches. For that reason we have Vedanta. Teaching of Vedanta is crucial to enable us to properly understand and properly interpret Vedic texts and the teachings contained in them. Every Hindu who is serious about adhering to Hindu teaching should properly learn at least the basics of Vedanta teaching. Without learning Vedanta one will most likely remain to be just one ignorant Hindu in this world, one who has missed the wisdom, without been able to understand the aim and substance of the Vedic texts.