Engine Belts And Pulleys problems of the 2006 Chevrolet Silverado

I own a 2006 Chevrolet Silverado with the 5. 3 engine. I purchased my truck brand new and now have approximately 115,000 miles on it. Recently, I noticed a knocking sound coming from the engine and brought it to a gm dealership thinking it was a pulley or other minor repair. Instead, I was informed it was a bad cam rocker arm roller bearing. They proceeded to repair the issue and my total bill came to $3,242. 84. I did some research on my own and found that gm has been aware that this part is defective on 2005 through 2007 5. 3 engines, however, this part has never been recalled. With the amount of miles I have on my truck (over 100,000), it is no longer under warranty. In my research, I learned that this part is either an engineering defect or a supplied part that gm did not adequately contain before shipping the bad product to their customers. After numerous conversations with gm, they informed me that their engines basically do not last over 115,000. I have owned Chevrolets for over 36 years and have not come across any engine issues which is why I continued to buy them. Even after confronting gm with my findings, they are not willing to reimburse me nor are they willing to recall the defective part.