Gog Magog civil war with the west

[Gawdzilla Sama]

Any stable environment will help. Hereditary empires are perhaps the least flexible of the available options.

too prolonged a stable environment discourages progress, periodic instability creates opportunities and demand for progress.  Imperialism is both also a natural outcome of a periodically unstable world, and competing imperialism by several powers is one of the key mechanisms that maintains this periodic instability.

I didn't say "static", I said "stable". Being able to KNOW with some certainty that you can go to the market and sell your eggs, knowing that a strange army isn't going to confiscate your livestock, et cetera.