Ah the “scientists hate God” delusion.
And it is evidence that only marsupial mammals lived that long ago, and placental mammals were a more recent development that edged out marsupials everywhere except Australia.
Just as Antarctica is evidence that when it drifted too far south, the animals that inhabited the Earth were far different than the ones that inhabit it today.
Not so. There are marsupials in the Americas.
Lack of evidence is not evidence of lack.
What alleged evolutionary advantage would placental mammals have that would allow them to edge out marsupials? And if that was the case, why the success of marsupials in succeeding in some places and not others?