A capitalist system is built on the idea that holders of capital actually deploy that capital, rather than horde it.
If capital holders don’t actually deploy that capital and compete with each other, then you don’t have a capitalist system anymore. You have a feudal system, where asset holders extract resources through rents, rather than capital deployment and risk taking.
Would this not still be the case even if labor wasn't entirely outpaced by capital?
Can you point me to the data showing how much capital is horded?