Capital deepening accounts for most of the remainder. All else being equal, domestic investment would raise future labor productivity and thereby help provide for our aging population. But the incremental benefit of additional investment may itself be affected by aging.
With slowed labor force growth, the amount of new equipment that can be used productively could be more limited, and the return to capital investment could decline as a consequence. Yet it is possible that the return to certain types of capital - particularly those embodying new labor-saving technologies - could increase.