I think the discussion on Buddhism in our forum is proceeding on sweeping generalisation. First, the division of Buddhism was not just two-fold, it was four-fold i.e. Sautrantika, Yogachara, Vaibhaashika and Vijnaanavaada. Theravaada (the name by which Hinayanaists refer to themselves) spread to SE Asian countries while Mahayana Buddhist to the Sino- Asian region. Kumarila and Shankara were alone not responsible for routing the Buddhist, it was accomplished by the Nyaaya school i.e. the Hindu-logic if I may say so. The Hindu-Buddhist interaction was very much active as late as 9th Century A.D. It was after the composition of the book Bauddha-dhikkaara or Atma-tattva-viveka by Udayanaacharya in 10th C.E that there was no one left on Buddhist side to effectively counter his arguments. So Buddhist school of logic was very much alive and active even after Shankara and Kumarila. Another reason for the disappearence of Buddhism was that the layman couldnt identify himself with the Buddhist school in India which was mostly wrapped in Sangha structure. Whereas Jainism survived as the Jainism allowed the layman to follow its principles outside its monastic order, so we have sramana as well non-sramanas in jainism, even today. The point is that In Jainism there were provisions for a layman to lead a perfect life with all necessary religious practices and ceremonies.