I always thought that was a nice fiction but without some serious evidence to back it up it will likely remain so. You'd expect at a minimum either some fossils with unique properties or maybe even a descendant alive today since apes are still here as well on the land. Absent both it looked like someone had a neat idea and attempted to rewrite history to match the idea based on cherry picked data, rather than that a piece of evidence was discovered that didn't match the view up to that point requiring a re-thinking of how we got here.

The accepted explanation seems to be - by far - the simpler of the two.