Precisely. Inequality only drives progress when people people believe it can be overcome. That's the basis for the American Dream. When people no longer believe that, as is the case in large parts of the US and EU, it only breeds resentment and drives down productivity and societal progress.
Historically, people made little progress in circumstances where they could not amass and defend wealth. Property rights and working public institutions is what allows people to stop spending their entire time defending what little they have and instead figure out how to improve what they amassed (in other words progress).