For many centuries Buddhism and Brahmanism coexisted in the Indian subcontinent. This book concentrates on the way in which the two, after an initial period of relative independence, confronted each other, both in and around the royal courts and in society at large. In this confrontation, Buddhism was strong in philosophical debate, but could not compete with Brahmanism in the services it could provide to the centres of political power, primarily ritual protection and practical advice. Buddhism evolved in both areas, providing practical advice to lay people and rulers from early Mahayana onward, and ritual protection in its Tantric developments. Some of these developments came too late, though, and could not prevent the disappearance of Buddhism from the subcontinent. http://www.brill.nl/default.aspx?partid=227&pid=44969
Except for the early Mahayana part, which is not necessarily supported by evidence, if one is to belief G. Schopen, the above is an interesting assessment:
"... even after its initial appearance in the public domain in the 2nd century
[Mahayana] appears to have remained an extremely limited minority movement - if
it remained at all - that attracted absolutely no documented public or popular
support for at least two more centuries. It is again a demonstrable fact that
anything even approaching popular support for the Mahayana cannot be documented
until 4th/5th century AD, and even then the support is overwhelmingly monastic,
not lay, donors ... although there was - as we know from Chinese translations - a large
and early Mahayana literature there was no early, organized, independent,
publicly supported movement that it could have belonged to."
-- G. Schopen "The Inscription on the Ku.san image of Amitabha and the
character of the early Mahayana in India." JIABS 10, 2 pgs 124-5
I think far more interesting and useful would be the sort of thing Gombrich talks about in his more recent books, which are the obvious responses by the Buddha in the suttas to brahmanical ideas. Now, seeing that synopsis, I can certainly wait.