Wall Street has a finite pool of dollars. Is it better to speculate that money into, let us say, 2,000 corporations or limit that opportunity to 1,000?
By limiting investment opportunity you get overpriced corporations. For the same money you can invest in two corporations with profit-earnings ratios of 8:1 that may have twice the employees making double the profit (earnings) than with one corporation that has a ratio of 16:1.
Wall Street is economically (job creation) inefficient for the 99 percent but extremely financially rewarding for the 1 percent.
Lowering the capital gains tax and repeal of Glass-Steagall allowed Wall Street to control investment and gave it the power to drag its feet and drag the economy down.
In 1997, the capital gains tax rate was lowered from 28 percent to 20 percent, resulting in the dot-com bubble. In 2003, the capital gains tax was reduced to 15 percent, resulting in a Wall Street's total financial meltdown.
Repeal of Glass-Steagall (1999) has allowed Wall Street equity banks control over commercial banks that serve Main Street. Banks aren't lending to Main Street because the money is being used to prop up Wall Street.