Ever pull an engine apart, that normally went 8K miles between oil changes, with regular oil?
People are lazy....ask them the last time they checked their oil level?
GM says it's "normal" to lose a quart in 2000 miles....so driving that old 3.8, you could have 1/2 quart left in 8k miles.....it's two main purposes are to lubricate and remove contaminants in the system......those contaminants build up in a vehicle driven that long between changes....I'd rather pay for a couple extra oil changes than an engine...