When we look at this question of what explains future growth, it doesn't seem to be very closely tied to accumulation of things.
Most of humanity's wealth isn't made of physical stuff. It is intangible.
That encompasses raw labor; human capital, which includes the sum of a population's knowledge and skills; and the level of trust in a society and the quality of its formal and informal institutions.
Worldwide, "natural capital accounts for 5 percent of total wealth, produced capital for 18 percent, and intangible capital 77 percent."