> and for some reason or the other were not really able to colonize Europe/Asia and kept venturing south until they ended up in Australia
Any people that did settle in Europe to the north during that first pass through further south some 70K years ago very likely were pushed back by the worsening conditions preceding the advance of the Last Glacial Maximum (dry very dusty air, poor vegetation .. and later ice everywhere).
Following the path of best land with least resistance led to following the tropics mostly by land, consistent year round conditions, no winters to store food for, etc.
Any people that did settle in Europe to the north during that first pass through further south some 70K years ago very likely were pushed back by the worsening conditions preceding the advance of the Last Glacial Maximum (dry very dusty air, poor vegetation .. and later ice everywhere).
Following the path of best land with least resistance led to following the tropics mostly by land, consistent year round conditions, no winters to store food for, etc.