There is no such thing as pure evil or pure good. Most of life operates in the grey zone between the two. I think this show really shows that. The storyline and character arc show that even the most morally driven people can never the less do bad things in the service of their own egos. As for TV and media promoting a decline in moral values. I think your view is far too simplistic. As long as there has been any kind of art, philosophers, politicians, and religious leaders have complained that it leads to a decline in the moral fiber of the populace. However, this kind of criticism is always a veiled attempt to impose a moral order that usually turns out to be just as corrupt if not more corrupt than the art form it was meant to protect us from. The bottom line is, people are smart enough to use their own critical faculties to decide what is right and wrong. I doubt most people are blindly following what TV tells them to do. In fact, it is shows like this that raise interesting questions that often people don't ask themselves.
This show is in fact not driven by any morals just the selfish interests of the characters. There are plenty of things in life that are pure evil and pure good. Murdering innocent people and raping children would be an example of pure evil. Feeding the hungry and promoting ethical behavior would be an example of pure good. The show billions in my opinion is "pure evil" because of everything it represents. I do watch the show and enjoy the story even though I find all the characters to be terrible because it really does accurately portray what goes on in politics and wall street. The point is not that people are not smart enough to discern the right from the wrong it is what popular culture has become. We are being presented terrible role models through tv, movies, and music. I am not advocating for imposing anything on anyone. I am simply giving my opinion on the show.