Are some of the supernormal powers a direct contradiction to old age, sickness, and death being unavoidable?

If a supremely enlightened being can become many, walk through walls and dive into the ground as if it were water doesn't this mean that he is not dependent on his body and can actually make the body into anything he wants? If he can become many couldn't he just manifest a new body? I have yet to come across even one case of any of the supernormal powers that has been scientifically confirmed. Usually after doing some research on claims of these powers I find an explanation that completely debunks them as frauds. I don't want to know if these exist in order to gain them but because I want to be aware of any discrepancies with in Buddhist texts in order to better fully understand the Dharma. For me truth is the highest goal so separating fact from fiction is a must.