Cycles of war&empire
It seems to me that there may be slight misrepresentation. Anyway, I would replace inequality by 'extreme inequality' using some thing like Palma index.
One of the comments is more to my liking, by 'akarlin'
"(1) Rising inequality as something associated with fragility was a feature of Malthusian-era economies, but not because of inequality *per se*, but because said inequality was usually the result of Malthusian stresses (and the banal consequences of Ricardo's Law of Rent). Once populations bumped up against the land's carrying capacity, surpluses were very low to non-existent, so shocks such as droughts, a succession crisis, a nomadic incursion, etc. that could have been (and were) weathered easily in the earlier days of the cycle could now instead translate into cascading collapses.
(2) The post-industrial system is a very different ball game and little of the patterns of Malthusian cliodynamics apply to it (for now, anyway... heh)."
The second part is not clear to me. The crucial problem seems to be that surpluses become low and share of the surpluses to the extent when a large proportion are at the subsistence level .