More money than brains syndrome.
Hardly.
Had you known the details, you might have said otherwise. The fellow who bought the GT for 600k did so because he can use the amount over MSRP as a charity tax deduction. A high net worth individual can get a minimum of 50 cents on the dollar off his taxes for such a donation. Properly structured, even higher offsets are possible. And he will.
There are huge amounts of funds being spent on items which benefit charity, as this sale did. Either the buyer can simply roll over and give his money to the IRS, or, he can find a venue to funnel the funds into a noble charity.
Why is buying this car any different that a charity silent auction where someone spends 10 grand on a TV sold for charity?
The buyer of this car, as do others, knows full well that he is not paying 600k just for a car, but that the funds above MSRP are going to charity.
The 5.5 million for the Snake is money well spent. The buyer owns the largest Mustang Collection in the world and got a one of a kind car.