Workers are cheap. There is no living wage here. Environmental and safety standards are nonexistent. The business is highly profitable … for the small group of people who own it.

In Bangladesh, men desperate for work perform one of the world’s most dangerous jobs. They demolish huge ships in grueling conditions, braving disease, pollution, and the threat of being crushed or stabbed by steel sliced from the hulls.

The Ship-Breakers, National Geographic, May 2014

The life span of such ships is roughly 25 to 30 years. … But the rising cost to insure and maintain aging vessels makes them unprofitable to operate.

This is true for aircraft also. The thing that wears an aircraft is the buildup of fatigue cracks in the structure. Every time you land, every time you pressurize, you form tiny cracks that eventually propagate. I wonder where old aircraft go.