sustained growth refers to having growth of living standards, per capita income or GDP over a prolonged period, preferably for never-ending time. How to offer such growth to a growing population from depleting natural resource stock is an issue.
Fortunately, we have the ability to gather knowledge to produce ideas for deriving increasing economic value from per unit of natural resources, and also labor. Moreover, a slight variation of growth rate, say 2%, over 50 years make a gulf of difference between nations.
The focus should be on creating and adding ideas to products and processes to attain desired sustained growth.