Pricing years 2 and 3. Every company raises rates for current customers. They figure that once you're set up you're less likely to switch to another company than if you're choosing at the outset.
It is a hassle to switch. At a minimum you have to wait half-day for the service guy to show up for the install. Then there's returning equipment and for some people changing email addresses (although anyone who uses an ISP email address deserves the hassle).
That said, RCN's prices kept going up for me so I did switch.