They can say what they want, but it is a simple matter of economics. They charge the number that will result in the greatest profit. If that's $50, then they charge $50. If it's $10, then they charge $10. They get hurt by piracy, but it doesn't affect what they charge. Your PS3 example illustrates this.
And this is your right. No one is requiring you to pay those prices. What you cannot do, however, is demand a product at the price you want to pay, and then steal it when you don't get it.
Right. Because they were the first company to bring a desirable product to the market, the supply was very low relative to demand, and they were able to charge $6500. As the supply of 42" LED TVs has increased, the price has gone down.
They surely do have the same principles. The gaming companies charge a price that they think maximizes their profits. If a game doesn't sell, the price drops. If it does sell, the price stays the same. I remember when the Wii was announced at $250, and everyone bitched about the high price, but then they couldn't keep stock in stores for months while completely dominating the market in total sales. Obviously, the price was too low, and not too high.
You're absolutely correct. If people stopped spending the prices being asked and instead chose not to play those games or systems, the prices would come down. In the past, you've seen products fail because the price was based on production cost rather than the supply/demand curve (the 3DO, for instance), and people weren't willing to spend that kind of money. Piracy doesn't change the prices, but it does increase the cost of production relative to revenue. So rather than increasing costs for everyone, what pirates are doing is likely preventing some games from being produced, which is far worse.