Comment by snowwrestler

The Alvarez hypothesis is notable not just because of its power in explaining the Cretaceous mass extinction, but because of its Copernican-like effect on paleontology.

Up to that point, it was a matter of belief among paleos that bolides were not a significant factor in the history of life. Essentially, that the Earth did not experience frequent or significant impacts after the initial formation of the solar system.

The evidence supporting Alvarez became so compelling that it not only became accepted as the K-T cause, it opened the door to considering bolides for all sorts of previous extinctions--an idea explored by Raup in his book Extinction. It made "sudden catastrophes" acceptable as a serious research subject for the first time since Lyell.

Prior to Alvarez, it was a matter of faith that the K-T boundary must have a solely terrestrial explanation, and the Deccan Traps were elevated to the most likely candidate. But it just shifted the need for explanation--why was there sudden globally catastrophic vulcanism? You say "India hit Asia" but that was not a sudden thing, in fact it's still happening today. Hot spots are still active today. It never really worked, but it was the best they had (or were willing to consider at the time).