Fossils are observed to form under heat and pressure. Not millions of years.
On the other hand, actual dead animals in the sea tend to float and bloat and rot, and then get chewed up when (if) they finally hit the sea floor.
Not lie there peacefully, waiting to get covered by sentiment and transformed into rock over 10,000 or a million years.
It takes a long time for elite-pleasing lies to get torn down. But the work does get done.