> China has the world's second largest economy and is growing at an astronomical rate.

Far from astronomical. 6/7%. It's very good compared to developed countries but the key for percentages is always understanding what is the original value you are growing from. China was a huge country both in size and population that began a transformation into a modern economy. They'll, sooner or later, become the largest economy in the world. But these growth ratios won't be sustainable. They'll stabilize around 2/3% once they fully develop their economic potential.

I'm not sure that there's actual scientific evidence for this, but my overall observation regarding growth is: unless you're some sort of tax-haven, growth once you've reached middle-income economy status is much harder.

China can't possibly become a tax haven: too many mouths to feed.

And their per capita GDP is smaller than Romania's. When was the last time you heard someone praising Romania's standard of living over the US's?

I mean, from many points of view I wish they'd keep up this growth because they'd take us to Mars within 30 years if they did, but I can't possibly imagine how they'd keep up rates of growth of 7%+ once the vast majority of their population has already been taken out of subsistence farming.