Comment by technotony

It's less that they won't spend it, and more they won't invest it. As you point out if you can get exposure to global capital growth by keeping your money in cash you will do that. This starves the world of risk capital being invested in new projects, the net benefit of which is responsible for capital growth. So nobody invests and technological progress drives to a halt (well maybe governments invest in military technology ands whatso but net investment in risky tech drops).