The Webb Telescope is scheduled to launch in 2014. The Hubble needed servicing to make it until then, plus they are enhancing it to make it better. Perhaps it will last past the launch of the Webb and will still be useful, since the Hubble and Webb are designed for different missions.
Holy cow! I just read that the Webb is going out over 1 million miles. That’s certainly different from Hubble, to be sure.