It takes a lot time and money to develop a new gruppo - like several years of development and testing. Then you develop processes to manufacture it. Then there's workwide distribution from where it's made and stocked and stored to your LBS, transportation, stocking and inventory, warranty costs, and maybe the biggest is advertising and marketing (look at the number of sponsored team each company supports, and take a look at every new cycling ad and read the what Sram does just to get in the marketplace. Add all that up and divide by the number of sets sold before it's time to replace that with the next version.

There are three major suppliers plus many more making pieces. That's enough to establish price competition. The prices aren't all that bad