Capital gains taxes and crashes

This is current tax receipts, but I checked them against income taxes only and it is pretty clear this is mostly capital gains. Notice they peak just before the grey bars. Not unusual, capital gains taxes drop when the market crashes. But we have a large peak this time, and that looks like a long fall.  Most of that capital gains are the very large players leaving the market.

Seems weird to me, and the excess reserves account at the Fed is piling up, just like this chart.  Why now?  Government debt is coming due, most likely.