you're missing my point, and maybe that's my fault. For instance, if you have big tires, and a poor alignment, that has to put unusual stresses on these components.
Case in point: My son and I replaced the ball joints and bushings on my son's 00 Dakota R/T @ 80k miles. Those things have unusually large tires, oem. We rough aligned it, pretty well, and he drove it a mile and a half to Les Schwab Tires for an alignment. By the time he drove it back from the alignment shop, the setting had slipped, due to improper tightening of the bolts. He took it back, same result. We had to take it to a frame shop, by that time the lower pivot bolt hole had elongated and needed to be welded up. The factory didn't mess that up, it wasn't wear and tear, it wasn't our work. It was poor alignment/service and those damn huge-*** tires that put a huge strain on these components.