1. If you're of the right mindset, and have enough money, to buy a very expensive bike, you're probably also the type who will take extraordinary care of the bike (maintenance, etc.), as a way of protecting your investment. Maybe that's one reason a $20,000 bike lasts longer than a $7,000 bike.
2. In the auto industry, customer satisfaction polls show that satisfaction ratings usually increase as the price of the car increases - ie. the more expensive your car, the more likely you are to express satisfaction with it in a poll.
Auto experts were perplexed by this because they knew there were lots of expensive cars that really stunk. Then the psychologists got involved... they discovered people rated their expensive cars higher, not because the car was better, but because they were embarrased to admit they paid that much money for a lousy car. Maybe the same with motorcycles?