[ComteDeLaFere]

-> They stagnated basically because there was little to no fighting.

A fair assessment, but now I realize that another way to say this is -

They stagnated because there was little to drive innovation.

Stated this way, it at least makes us consider that there might be an alternative to constant warfare as a driver of progress. Maybe recognition of this is some kind of societal turning point as well?

[pixl97]

War may drive innovation, but it may also have other purposes. Like resetting service and management economies that spend lots of effort keeping themselves running but not producing products. People think that the more efficient businesses always win are wrong. A bureaucratic sector can wedge itself into the legal system and enforce inefficiency.

[hx87]

Modern capitalism, combined with the expectation that things should improve over time (which wasn't very prevalent until recently) can be one hell of a driver.

[redwards510]

> alternative to constant warfare

How about the existential threat of climate change? Either way though, the driver is survival.