Ah, another example of multiple equilibria! Investment in intelligence and defence spending can lead to entrenched interests which demand continued spending. The famous military-industrial complex. The coordination needed to break out of this equilibrium can be made much harder by multiple states each needing to meet the defence spending of their peers. It's hard to cross from high defence to low defence spending (consider unilaterally disarming during the cold war. Borderline impossible. You need careful coordination through treaties) and also difficult to go from low defence spending to high absent some obvious threat (you could perhaps model appeasement as an example of this, though I think other factors dominate).
Notably, one of the reasons that the military industrial complex can be hard to unwind is that it works well for capital and workers. Consider all the programs you've heard of which boast about providing jobs in every single state. Whether these different equilibria are better or worse for labour (or fractions of labour giving you your diverging K-shape) is a separate question and potentially changes over time.
One historical event you could model as a change in equilibria was the industrial revolution. Instead of elites consuming economic surpluses, the economy change into a mode where those surpluses could be reinvested in productive capital, new technology, and manufacturing in a self-reinforcing cycle (of course these avenues didn't really exist before). Famously, within this new equilibria, labour did not do well at first; awful conditions in factories with terrible life expectancies. But those workers' grandchildren lived lives of relative prosperity as a result.
All of which is to say, the existence and description of multiple equilibria in economies is a different question from how labour and capital fare in those equilibria.