Do you think that this McLaren is the only one in the factory's collection? Considering McLaren's history of winning F1s, the museum must be full of obsolete F1 cars, including duplicates, test mules and spares. Why not let someone else have one? Do you really think that McLaren sold for money? Of course they did. They got $6m for the car. And they got it for essentially nothing, as they have another (or maybe 3) in the back... But, you know, $6M is nothing when McLaren is developing an entirely new F1 car for next season. But every bit helps.