Might the opposite be true?

It seems odd to me that when taxes were progressive (like 70% on top earners back in the 70s and 80s) our economy was doing well, or at least a lot better than today's economy. When we reduced the top tax rates and got rid of banking restrictions (Bush tax cuts and repeal of Glass-Steagall) our economy started its downward slide, tanking in 2008. The "job creators" (the top earners) now paid far fewer taxes on their income and our financial institutions took crazy risks and invented products that were economic time-bombs. Could it be that the wealthy, when taxed more heavily, have an incentive to make more money thus creating more businesses which means more jobs and shared prosperity? And is it possible that when our financial institutions are regulated they actually help create a more stable economy? Just asking.