MoSo let us tackle this question from a purely academic angle and not from any religious or non-reigious bias. Once again, this post will require some patience from those who don't have strong and long attention spans. I will try to connect the dots for you without trying to portray one religion as the absolute truth over the rest, and hopefully, even tackle it from the athiest's angle.
But more importantly, I would like to keep matters in perspective here because this thread definitely 100 percent positively has an agenda. I don't want us to lose sight of why these questions are being asked (you need only see who started this thread and the line of questions that has been raised), so here goes:
The morality of religion will always be questioned. Humankind has evolved over thousands of years regardless of what some people believe to be true about our origins, history and past. The definitions of what was considered righteous or normal have also changed over the years and so have the virtues of morality and ethics. I will always defend the point that religion has been at the forefront of setting the standards for morality and ethics and humankind has needed that guiding hand, whether you believe any religion to be divinely ordained or not is not the point in my argument. Its inconsquential. With the modern day "evolved" humanity, its easy to walk into the trap of arguing "Well, I know very well its not ok to lie and steal and kill, I never needed religion in my life for me to know how to live my life and to decide right from wrong".
But let us not confuse that mankind in the past never had that "evolved" thinking. There was no modern governance and law and order. Whether you believe there is a higher power sitting up there who decided to send us guidance from time to time or not, you simply cannot deny a guiding hand was needed. Now it does not matter to me if you think these holy men or messengers in the history of mankind were simply men thinking they can come up with this stuff like cult figures of today to spread their message for the betterment of mankind or not, that they used the deception of God to spread their message and convince people...... what I want to prove to you is that it was needed.
So the larger point is: Mankind will always need a structure and guiding hand to lead it through the ages and it struggled and would have crumbled in the absence of any such structure. I believe there was a debate here on the separation of church and state in the US and I argued the point that most US laws are still derived from religion and I think in light of my comments so far, you will probably start to see what exactly I have meant by that.
Now let us go back to the question of paganism/polytheism vs monotheistic or Abrahamic religions. What were the flaws or aspects of the former is the question raised by
@rpant_gabba and how was the answer found in Abrahamic faiths?
Paganism or polotheism brought various deities to the table. People picked a diety and worshipped it either based on their preference, needs, profession, insert whatever reason here. There is a god of fertility, agriculture, sea, revenge, and etc, etc, etc. They are all disparate, sometimes disconnected and provided conflicting messages. Not exactly the sort of stuff if you want a structure and organization to humanity and society. Monotheistic religions tended to bring everyone to the same table and standardized a lot of this stuff... once agains its irrelevant if you believe that to be a divine move or human machination. So this fundamental difference in theeology is just one point in the debate which I believe is more important than the rest of the divergence.
Now, if I were to speak about other flaws of a paganistic society, I will point to the situation in the Arab world prior to Islam because thats where I am most read. The pre-Isalmic Arab society was in disarray. Women had no rights. Infanticide was normal. Then there are other attributes which have evolved over time and are probably not looked down upon by humanity anymore, such as drunkeness, engaging in drugs, polyamory, homosexuality, prostitution, etc which created other challenges in those days that can probably not be a big deal now. I would say spread of STDs, questions of paternity, protection of women, are only a few such examples that probably are no longer viewed as challenges today.
Other challenges included the lack of a central government or little to no framework of law. For reference, I am going to use a completely neutral source here that describes some of these conditions:
https://courses.lumenlearning.com/s...r/culture-and-religion-in-pre-islamic-arabia/ ... hoping this will protect my against allegations of pro Islam bias here. But if you are interested you can research and I am sure find all my claims regarding pre-Islamic arabia to be justified through independent and neutral sources.
In short, I would say the flexibility in views we have today and in this modern age was never the case in human society through the ages and what you might consider ok such as homosexuality, polyamory, etc resulted in societal challenges that monotheistic religions tried to counter with their well defined framework.
If you believe Abrahamic faiths to be divinely ordained, you can argue the guidance was adjusted by the Almighty based on the changing norms of humanity and were sent on humanity to assist in its evolution and not to get them to transform overnight. So the message was sent gradually, addressing the political and social zeitgeist and conditions of the era with a goal to providing structure.
I am sure the Indian posters here will argue that the Hindu society operated without these challenges and did not need the monotheistic guidance. But its one of those debates that I personally cannot counter since I don't have much knowledge of Hindusm except what I have read here and there. One issue I do see is the caste system based on profession and how that did not truly provide for any equal rights for all within a society. One can argue that has changed over time though. But what did I know? I just tried to make sense of the question in light of what I know as a Muslim and a human being and tried to rationalize to the best of my ability. Hopefully this is not taken as a slight on polytheism or atheism.