Long and the short of it is you're going to have to provide references on that Psychoak, because I don't see anything in the stats to bear that out, and it would be pretty a pretty big footprint if it were true.
The 1986 Tax reform dropped the top income tax from 50% to 28%, while removing the Capital Gains from being exempt to being taxable, and was designed to be revenue neutral (i.e., balance the two of them out so that the gain in the one would balance out the loss in the other), so, given that the top brackets have 90+percent of the wealth and a slightly lower percentage of taxes, you would expect to see a major drop in tax revenues.
The actual statistic don't show that: (Numbers in Billions)
Year GDP Personal As % Income Capital Gains
Taxes of GDP Tax Rate Tax Rate
1985 4,180.7 437.7 10.469% 50% 0% (Exempt)
1986 4,422.2 459.9 10.399% 28% 28%
1987 4,692.3 514.2 10.958% 28% 28%
1988 5,049.6 532.2 10.539% 28% 28%
During the entire period from 1985 to 1988, the entire difference was under 0.5% of GDP, or ~5% of tax revenues.
Now, with numbers that big, 5% of revenue is a pretty big number - but less than the net worth of a Bill Gates or Warren Buffet and *lot* less than you would expect if there was a major drop in capital gains investment. Other stats for the period (Unemployment, the prime rate, CPI et al) are just as consistent.
I don't have a closer breakdown of the tax rate figures to break down into capital Gains and Income tax revenues, so it's feasible a closer look could support your thesis - but a first look just doesn't support it as being a valid statistical model.