On the other hand, you can partly derive the political system from technological changes too (I.e. without the socialist scare you don't get fascist regimes, and without the industrial revolution you don't get socialism)

People have made arguments stating that Trump is a manifestation of anti-social behaviors that are reliant on reinforcement through online echo-chambers which remove any form of social-moderation. The extent of which I agree with this arguments I'm not quite certain, but I do think from a sociology standpoint it's foolish not to investigate how the internet's changes to how we communicate have lead to changes in how we think, and potentially our collective political leanings.

Media theory is really fascinating when you dig in to it, and we should be mindful that we're still in the early days of the internet in the grand scheme of things, and society is still adjusting to what will forever be the new normal.

As for me, I'd like to think that a bit more nuanced approach is better. Yes, stirrups might enable men to use horses in new ways and to brace themselves on horseback. But this sort of expensive heavily armoured cavalry cannot exists in a vacuum. It needs a class of wealthy people who can buy armour and horses. The wealthy need some sort of motivation to train themselves as warriors and so on. If you are interested in the subject, The Making of Europe: Conquest, Colonization and Cultural Change, 950-1350 by Robert Bartlett [1] is an excellent book on the subject.

[0] https://en.wikipedia.org/wiki/Technological_determinism

[1] https://www.amazon.com/Making-Europe-Conquest-Colonization-C...

A chicken/egg cycle, initialized by temporary imbalances that created a stable system: an increased advantage of cavalry over infantry drives up the price for "protection", which in turn feeds the horses. With less advantage of cavalry over infantry, the class system would have been much less pronounced.

In the spirit of "strange women lying in ponds distributing swords": a fluent socio-economic power structure was converted into an intransparent class system self-stabilized by the barrier of entry imposed by the inherent cost of heavy cavalry.

I agree. I think that a given technology has requirements and consequences that determine a lot about the society it is in, but it also presents various possibilities that will be determined by external factors, such as politics.