Cloning might ensure that people would live forever because when it becomes perfected, humans will actually be programed and their death will be within the program. Who would program a person to die? So, chances are good when it happens, the clone will not be programed to die. Short of a disaster or horrible accident that overrides the programing, like a train running over the clone and crushing it, there is a good chance that some would live forever because it would be programmed into their genes.
This kind of power is indeed scary. Consider the risks of such. It will be like a sci-fi movie come to life. But, think of how the pioneers of olden days would have felt about computers. See the similarity? The unknown things about the future usually frighten mankind. It could be a good thing for clones to live forever. We will just have to wait and see.