The change to Proforged Ball joints was because of the fall off in quality in Moog. They are far superior. Trend analysis found that the Moogs were failing at a ridiculous rate, causing failures and warranty issues.
The Hotchkis piece costs as mush as it does because they are made in America. and you're getting the best and most tested factory replacement suspension components on the market. Period.
I literally experienced the issue of Moog's "fall off" in quality first hand. The picture is how it came to me in new in the box. This is after the first set wore to sloppiness in less than one oil change/service period.