This sort of thing is very common on Mercedes' built from around 1998 to around 2004. It was a period when Mercedes body preparation and corrosion protection hit the pits. The component which collapsed is called a 'spring perch' and failures on W210 Mercedes E Class were particularly common.

However, I don't see Mercedes offering any goodwill over a fault with a 12-year-old car and I doubt whether even tough US consumer protection legislation would be much help. Cars are built to last six or seven years, and anything longer than that is a bonus. If a component fails that costs more to replace than the car is worth, the car should be scrapped.