This strategy works as long as there are more places (by volume) experiencing growth than decline. Since the trend is slower growth overall, there will be a point where global growth stops, and clearly then the strategy will start to fail.
Frankly, from a planet point of view I'd hope that point comes sooner than later.
This will play out in obvious ways (lifting retirement age etc) but ultimately the quality of life will increase overall until some sort of stable population number emerges.
Also, look at cities that have had a decreasing population, such as Detroit. They don't look so good.
OTOH in countries with decreasing overall populations due to birth rate and not lack of economic opportunity (emmigration), it might be possible to sustain high employment rates, low crime, and good quality of life. (There might be more need to fund social services, however, if the population is also aging).