It's not that markets are completely rational at all, it comes from supply and demand. If you exclude a large portion of your supply the price will go up. For

It's not that markets are completely rational at all, it comes from supply and demand. If you exclude a large portion of your supply the price will go up. For example, if I only higher people greater than 6 feet at my company, and my competitor doesn't care about height -- the wages will be lower, unless of course tall people are the cheapest to hire already.