What is capital scarcity or abundance? If we produce ever more, how it can be that capital suddenly runs out?

Although theoretically capital is any means of production (for rent), the overwhelming form of capital is money or financial instruments. The way money is "created" or financial instruments are structured, numerical abundance of capital basically means abundance of promises, ditto with scarcity. But a promise contract has two sides: the promised are credited with quite some power to expend, while the promisers find their freedom stressed, especially in hard times. A promise bubble produces a situation where promise entitlements are collected by increasingly smaller elite group, while promise dues start to weight (directly or indirectly) on the rest, with compounded growth. This is basically a neo-feudal order with a highly privileged minority and forever "indebted" masses.

I read somewhere (perhaps here) that the Anglo-Saxon economy dominates the planet precisely because of the power of promise economy. Other systems, without a mass of mortgage and other promises, are just very lethargic in comparison. An African anthropology study shows that tribes with culture of strong promise compulsions tend to displace looser tribes.

But of course, the risk of promise economies is that the volume of promises start to exceed natural resources and capacities. Unsurprisingly, that leads to enormous social stresses. We get indeed abundance of capital (aka promises) - and that is the stifling problem.