How long can a battery possibly last

My brother swears his ford ranger had the original battery in it for 14 years. He drove 43 miles each way to work and did little else with it. 254,000 miles on this two wheel drive, 4 cyl. when it was to roached out to much to drive anymore.. Rusted to hell, but only put one clutch in it and this I know because we did it. Wish I had a picture of this thing, the rust was amazing, he had riveted straps to hold panel sections together. The rear bumper fell of just before he junked it. He took the passenger seat out for storage because he didn't trust anything in what was left of the bed. My big brother is as cheap as they come. He lived out in the country and his wife made him park it behind the house. Bought it new and got his monies worth. It got great mileage and it ran perfect to the end.