If that were really true though, wouldn't a big company solve it by splitting itself apart into smaller parallel units all doing the same job as each other but

If that were really true though, wouldn't a big company solve it by splitting itself apart into smaller parallel units all doing the same job as each other but with shorter hierarchies and not wasting time communicating with each other? I think economies of scale still overwhelms the chain-of-command losses you described and makes big companies more efficient overall.