What does the phrase ’their ranks will swell but their tread will no longer shake the Earth as it once did’ convey in the context of the passage?

While many countries will try and achieve the same rate of growth as BRICS they will not succeed

The growth of BRICs countries had change the world’s economy in ways that any further growth will not have such a disruptive effect on the world economy

Developing countries have strengthened their fiscal systems in such a way that they will not be shaken to such an extent again

Poverty may increase as the gap between the rich the poor increase but it will never reach the same levels as prior to the crisis.

Citizens in advanced countries become much better off than those in emerging economies