A long time ago, I got into writing online quizzes. My masterpiece was a monster on the topic of how history gets revised for popular consumption. It's been a long time since I updated it, or checked to see if it was still working, but one of the key themes I noted in putting it together is this:
History is very nonlinear. It's not only nonlinear - different things change at different rates - but in every dimension it is non-monotone. Technology does not always move forward. New farming techniques are not always better. Sexuality has not steadily become more relaxed over time, but instead, has cycled through different eras of prudishness, puritanism, and permissiveness.
The Victorian era is a prime example. It was probably the height of sexual repression (as we commonly consider the term) in England - but while the stiff standards of "proper" female behavior marched forward, that does not mean the pre-Victorian era was even more prudish. In fact, the 17th century was a very earthy century in England, as we know from Shakespeare.
Another prime example that is especially worth noting is the Antikythera device - a mechanical computer dating back to around 150 BCE, which in sophistication, rivals the mechanical computing machines of the early 19th century. It would take almost 2000 years until western Europe recovered the sophistication of the Greek clockwork devices.
And then the mind just boggles. On some level, when I was young, I absorbed the lesson that history was a kind of progress. You always moved forward. And then, slowly, I absorbed a different lesson: History is nonlinear. Dramatically so, not just in the eyes of wild-eyed fans of ancient alien visits, or apocalyptic doom-bringers, but in the cold eyes of rational respectable historians.
Forces for progress exist, but as is normal in nonlinear dynamics, they are very difficult to model, and there are areas where they behave oddly, local anomalies, and oscillatory behavior.