[Beav]

Consider that with a strut suspension the lower ball joint is unloaded, in other words it doesn't carry the weight of the car, the strut mount and bearing does. The lower ball joint is just a pivot point and keeps the assembly from flopping around.

Typically, unloaded joints last longer than the car. Sealed joints have been employed increasingly over the years as they normally last longer than joints with fittings that allow lazy people that refuse to wipe the crud from the fitting before attaching a grease gun and pushing the crud into the joint.