Um, Last I checked, not many human machines can continuously operate up to 100 years. Most robots and machines like cars are considered "long life" if they last 30. Seems to me the human body is built to last.
Those capabilities -- self repair and energy collection -- should allow many orders of magnitude greater longevity. The fact that they haven't indicates that those capabilities are not optimized for longevity. Ie., we were not 'built to last.'
We were optimized for species-longevity through reproduction, not individual longevity. The fact that we've existed as a species for hundreds of thousands of years is more like what you should expect from something that is built to last.