One is a legacy system introduced by organized gang-rape 38,000 years ago. A vestigial brain type which has been steadily vanishing for the past 20,000 years and is being constantly replaced by the Saps brain, which is best summed up as a "brain" that doesn't seem to work. At all.
Sapiens can't live on stolen capital forever. Nobody ever does. It is the problem with people who survive by stealing or raiding the wealth of others, including their genetic wealth. Sooner or later, the best thieves are going back to that mud hut they came from.
The 'Thal brain which is largely responsible for any aspect of civilization which is good or life-affirming, has been outbred by the Saps weakest, craziest members for millennia. It is amazing there are any marginal hybrid 'Thals left ... but this tells you that these genes must have been very, very special to persist for so long despite their dwindling share of the chromosomal pool.
I am sure that Melonheads have contributed somewhat to certain aspects of civilization that reinforce hierarchies and power structures, which 'Thals are always working against. The difference being is that Melonhead innovations (like Edward Teller and the hydrogen bomb) always seem to be about dominance and death. Only the 'Thal makes everything better by simply coming into contact with it. They always seem to give so much away, even allowing themselves to be cheated out of their own profit from their efforts ... if it appears it can improve life a little bit for everybody else.
The Neanderthals were the good ones. All men are filthy rags before God but ten thousand Homo Sapiens put together never worked as much general benefit to all men as many Neanderthals did in a single day of their lives. They would seem to be the best sons of God, if heaven could be won by good deeds. Of course, that may be precisely the reason God despised Esau, who thought himself so good he was indifferent to his creator and perhaps took his pardon for granted.