To the best of my knowledge not everyone agrees to that hypothesis. One of the strongest arguments against it is that paleontological evidence is always incomplete. Holes in it that are treated in favor of the hypothesis are actually smaller or comparable to holes that appear just due to incompleteness.

Read the article. That's the subplot. We get to see just how non-scientific science really is. The true and current evidence points to an asteroid being the final blow to an already declining environment. But the status quo narrative so strong that egos and biases override facts.