Last time I checked human had small differences from canned food.
And why than bone marrow doesnt become a subject of same chemical degradation? It from the same category of non regenerative cells but AFAIK the only things that have impact on it is radiation, i.e. I never heard something like 'your blood is kinda shit because you are three digits number old'.
1. Your body cells and fluids are constantly being replaced. with new cells replacing the old. new fluids replacing the old. With egg cells there is no such replacement. it is the exact same cells her entire life.
2. Of course your bone marrow degrades with age.
You must be registered to see the links
TLDR your bone marrow slowly dies off with age and is replaced with fat over time as you age, as well as a variety of other problems.
And that is while bone marrow in specific keeps a colony of stem cells specifically to facilitate the replacement and regeneration of bone marrow to help last a lifetime.
That said, even as it happens you should still have enough to last you a good 120 years. especially thanks to some compensating mechanisms
3. of course people who are three digit old have shit blood. Where did you get the idea they don't?
Putting aside how cardiovascular disease is the number one killer in western nations (as that mostly focuses on the the veins and heart. although the quality of the blood affects those enormously). If we look at the blood alone we see
You must be registered to see the links
TLDR: older people suffer from blood that is more viscous, inflammation causing, has deformed blood cells, etc.