They are slowly appearing at wider and wider focal lengths. There is demand for them, whether they are needed or not. They affect the optics in a large way, and raise the price by a large amount as well.
There is little doubt that inexperienced photographers benefit from IS, they do not understand how to determine shutter speeds. I'm not referring to those who regularly post here, they understand for the most part, but those who just drop by their local best buy store to upgrade their powershot, expect IS and 10:1 zoom on their DSLR, and ... money talks!