I deffinately think GC is more like $75 (minimum) to $100 (maximum) rather then $20, I can't see any way to put it together for $20.
Although I don't agree with all the reasoning in that letter. Selling something dirt cheap isn't always the best option. It can make you just look cheap and crappy compared to the competition. But obviously if they were making them for only $20 each I'm sure Nintendo would at least be selling GC for $149 with 3 big games rather then the current offer of $189 with 1 big game.