Very interesting. It's sheer co-incidence, of course, that this extinction coincided with the arrival of the aboriginals.
Lately I have been reading such little gems as "the aboriginals have the oldest evolving culture in the world", they practiced controlled burning to manage the land, developed complex aquaculture farming methods etc.
Make of that what you will.......
And yes, of course it was aliens who built the pyramids etc, I thought everyone knew that.