How much do you think these prices reflect actual costs vs. jacking up the prices because of increasing demand? 30% increases seem like jacked-up pricing to me, at least in part.

At the low end it seems crucial to keep the cost down to get people to buy from their LBS instead of Wal-Mart. Those folks that buy at the LBS and then get good service may be buyers of better bikes down the road. People also sometimes get 'branded.' Buy a Trek commuter, then get a Trek road bike, etc.