In its place have come catastrophism, and punctuated equilibrium to explain the total lack of transitional forms and support uniformitarianism. We have ample evidence that dinosaurs existed. Job is an ancient gentile book, pre-dating Moses, that testifies of dinosaurs contemporaneous with man. The witness of the fossil record shows not just dinosaurs, but rhinoceroses and other mammals died off, as well. We have Bible revelation of God's judgment by the Flood.
Many world cultures tell the story also.
The Flood wiped out vast populations of living kinds. Great climatic change, quick freezing brought by hurricane winds, inundation and drowning, volcanism, and upheaval characterized the Biblical catastrophe. Massive deluvian mechanisms rapidly froze many animals, then buried them in tundra muck where they remained frozen to this day. Living conditions were greatly affected, longevity plummeted, and climate zones were established. The polar regions were changed from subtropical to severe arctic rapidly, permanently.