Yeah, that is odd. I had a 95 Yukon (1st year), 2001 Yukon XL, 2006 Yukon XL, and have bought/used for our construction company (subcontractor) 20+ GM 3/4 ton trucks and have never changed shocks for any reason under 100,000 miles (I managed our fleet). The Yukons were all sold with 125,000+ on them, stock shocks. The trucks were constantly on jobsites at full weight capacity, 2wd, and rarely if ever broke a shock. This was a mix of standard cab 8' bed and crew cab 8' bed trucks. Granted, they weren't all Ranchos, and over the years we did replace some high mileage shocks.
It just seems like, given the much higher number of vehicles and the much more abusive treatment my fleet went through, I would've run into trouble if GM were putting cheap shocks on their trucks. But, maybe I was just lucky and you weren't. Who knows?
I totally agree, though, if I had had 3 trucks with leaking shocks in 7000 miles or less, I wouldn't trust them either. Frankly, I wouldn't have bought the same truck with the same shock the 3rd time after it happened twice.