Another possibility is that aging is actually a side effect of some other important process. This would make it difficult to evolve ways to slow down aging without affecting the original process. My guess is that aging is somehow related to growth rates since organisms with longer life spans like humans or turtles often take a long time to reach maturity. Most forms of life need to reach full size as quickly as possible followed by a rapid stop in growth once full size is reached. Perhaps the rapid stop in growth causes problems with the body's repair mechanisms which ultimately lead to aging. This would be kind of like a business or city which experiences a sudden stop in growth that eventually leads to breakdowns as there is no longer enough money to maintain the infrastructure built up during the growth phase. The physics based theory in the article can't explain why similar forms of life age at very different rates (i.e. dogs aging 7x faster than humans) so something else must be going on.