So to me, it would be very hard to make an argument that it trickles up. It has to come from investment. And investment in the private sector is usually done by rich people, because you need money in the first place to invest and also because investing well makes you rich.
Also considering that the super-rich in developing nations are not that far behind the super-rich in developed nations, why hasn't their wealth trickled down and uplifted those developing nations? The reality is that developing nations have even higher wealth inequality, so refuting your argument.
I am from a developing country. There aren't a lot of super rich here. In fact there isn't much wealth at all. Having some greater gini coefficient doesn't mean you have more wealth, inequality really isn't a relevant measure.
If raising wages was the only component to development, Somalia could simply set their minimum wage to $50 an hour and watch the country soar. Wages follow development, not the other around.