My oldest bow of known age is my 1955 Bear Kodiak, it was built the same year I was born. We both turn 54 in June! I believe it is in better shape than I am for our age!! I still shoot it and have yet to hear any squeaks, creaks, or complaints from it. Wish I could say the same for my body!
I have a few bows which I know are older, just don't know for sure how much older.
I've only had three bows ever fail me.
2 of them were laminated longbows which I made using a batch of bad epoxy. They both collapsed at the fades, 1 on top, 1 on bottom.
The other was a Bear Bearcat T/D, with the magnesium riser. Upper limb collapsed at top of riser, never could figure out why.
But I believe most bows that are well cared for, will have a life expectancy that far exceeds its owners.