that capitalism as practiced from the Renaissance onwards has been absolutely dominant compared to everything else it encounters.

How does the last century of social democracy fit into this?

Unbridled capitalism creates a system whereby wealth flows to the top x%, who then out of luxury / boredom / freedom might create new shit. Science, for example, has historically mostly been done by white rich dudes with way too much money and time on their hand. It's a direct consequence of the power and wealth structure that capitalism generates.

However, social democracy and in particular wealth redistribution through serious taxation creates the much more preferable social order whereby there's a less rich top x%, but the rest of us plebs has enough of a social safety net that innovation can come from a much larger portion of the society. Which is beneficial for all of us, and also for capitalism in the long run, but isn't a system that has the evolutionary strength to survive against populism and fascism as the past decades have shown. I could argue that the postwar social-democratic (pre-Reagan, pre-Thatcher) capitalism is a better version of capitalism that lost to the current strain of short-sighted capitalism, even though it is better, which seems to me to fly in the face of the idea that the most powerful version of capitalism will win out.