Thats me, you do what you like and ill do what i like......
Since you brought up diesels and other makes (semis, etc) other than chevy, for the record, i have an 08 accord commuter car (bought new) with 300,000 on it now and i run full synthetic. i change the oil between 9-12k and add a 1/2-1 quart at about 5k...i do about 150 miles a day (5 days a week..150x5=750x4=3000) which means id be changing the oil every month or so based on 3k schedule. I dont pay anyone to do it and im certainly not crawling under that car every month to change the oil.
My tahoe however, gets an oil change every 3-5k, 3 months or before and after any long trips whichever comes first and maybe, maybe it gets driven 100 miles a week.
Theres your fact based thinking right there..