One such candidate is (multifactor) productivity growth. Relatively weak growth of productivity over much of the past decade would have weighed on the return to capital and reduced the incentives to add to the capital stock in nonmining industries (Graph 7). (In principle, this effect should already be reflected in levels of Tobin’s Q.)
If productivity growth were to remain relatively low, that would weigh on overall growth of the economy. Low growth of investment would naturally follow from low productivity growth, but it would not be the cause of weak growth of the overall economy. In any case, it’s hard to know exactly what productivity growth is likely to do in the future.