Did you pack in mylar with O2 absorbers? I had some long term storage items before we moved from one state to another. My beans were still useable after five to seven years. I’m curious if maybe we were just in the window or usable or not.I also thought dry beans keep forever and bought a lot of them as cheap insurance before Y2K, and when we moved to where there was a Sam's Club.
They may keep forever but they are useable for much less than that.
My son-in-law's mother came to visit. She cooks beans and rice nearly every day. She tried to make some for us and that is when I discovered my few attempts at making beans using dried bean did not fail because I did it wrong. They failed because when dry beans are stored too long, they are not usable. She tried very hard to be polite but I will never forget the look on her face.
Basically, they do not absorb the water they are soaked in whether it is the long way of soaking them or the short way. Even with extra, extra, extra long soaking times. I tried that after she left. Then threw them out in the pastures. I didn't think they would compost in a reasonable timeframe.
My best guess is they were about ten years old when we tried to use them. Kept in a fairly dry basement.