कल्पान्तरे विश्वासटिप्पन्यः

(From : kAshyapa-kRShNa)

Alwar swamin said KSV had talked about this. He said there is not much proof about any temple before 2000 years back. Even the sthala puranas of each older temple like ranganatha temple and even melkote as being there for yugas, are mainly to enhance faith in people and not historical. Even the ramayana and any other reference are weak references to state that temple culture was so ancient. The vaidika period and post-vaidika periods were more yajna and upasana based, as explained in vedas/upanishads.

The whole stala purana regarding srinivasa perumal story is also recent : about 300 -400 years old. Shankaracharya has barely made any bold reference to temples. Hence they were all developed later.