This is simply false, the average Chinese or Indian is incredibly better off now than they were 100 or 500 years ago. In fact for the past decade many of the wealthiest countries (many Western European countries, and Japan) have seen barely any growth in living standards at all, GDP-per-capita growth has been concentrated in developing countries.
It's not mutually exclusive with enormous relative improvement at the bottom, from where people were to where they are now. China and India have all but ended open defecation and there's running water in places we'd never dream of a generation ago. Diseases are being eradicated saving huge numbers of lives.
Rich got richer contains zero information about how poor people fared - even accounting for relative numbers in your claim.