That's the weakness of human beings. In general, people (including those great traders) have tendency of being either panic or greedy, because we are not saints. Unless those traders are really blessed, just like Jesse Livermore, they were eventually forced out the market dreadfully.
Another issue with this kind of story is the tax of the capital gain, short term traders usually need to pay income tax (most likely 38% in this 200+ million windfall), instead of the fixed long term capital gain tax (15% currently). If this guy cashed out the QCOM positions without putting aside the taxes. Instead he put all the pro seats into the market again and the market crashed like 2001 or 2008. Not only his gain was gone, but also he would owed IRS millions in tax. BTW, he can not simply declare chapter 11 to wipe out the tax. Instead he need work with IRS to set up payment plan for the next 20-30 years. In 2000, there is a true story about a guy made a killing by trading Etrade stock, then lost almost all the gains. He had to work with IRS on the payment plan afterwards.
