Part of the sale issue for me, is that I sometimes already own these deep discount games. It makes it feel like there are less good deals.
Also some new games have what I consider to be really high base prices, so a 60% discount is still not near the impulse buy range.
The most recent suggestion I saw is that there were just more sapiens when they started interacting. Interbreeding must have happened, but with new groups of sapiens continuously arriving from the middle east, the neanderthal DNA just got more and more dilute. Eventually "pure" neanderthals no longer existed.