All throughout most modern history ... if you set up an economic system where you allow humans to gain unbelievable amounts of wealth and ask them or wait for them to share it, they never do and instead use that wealth to gain even more sums of wealth in a never ending cycle. I know plenty of wealthy people and they do share their wealth, just not in the sums you want to imagine - they share a few hundreds or thousands here and there but never enough to create meaningful change and never in the amounts to affect the growth of their wealth.