The Kindle Fire is a bad analogy: for one, it's priced more or less at cost, as Amazon is using it as a platform to sell their library of media. Secondly, they ship about 1 million units per month (5.5 million in one quarter actually). If there were a million bikers a month buying LED gauges you'd see a much lower price.
That being said, I wish the parts were less expensive too. You should try mountain biking - cranks machined out of aluminum that probably cost them $20 to manufacture and sell for over $300.