Also, you guys make it seem like these blazers are so unreliable. My dad has a 1982 k30 and the only problem he has EVER had with it was power steering pumps and belts. He had the engine rebuilt, due to user error- the engine didn't get enough oil don't remember the whole story.
The previous 2 posters have correctly identified the issue. Even new vehicles vary in quality from truck to truck. After 30 years of compounding that with owner maintenance habits, the variation between trucks gets to be downright huge. I'll give you two examples, from my own life:
I have done multiple thousand mile trips in my stock K10 with mostly original drivetrain. And I wouldn't hesitate to drive another long distance trip with it whenever the need arose. It's even on loan right now, 350 miles away. I bought it from family friends that had owned the truck since it was fairly new. Their maintenance wasn't perfect, but it was good, and the engine compartment still looked like new under its thick layer of dust/grime. Its history was known ahead of time, and that has helped me out quite a bit over the last few years.
My Suburban, OTOH, came with a whole host of problems inherited from its previous owners. Mostly due to shoddy maintenance and a hacked-up engine swap.

I'm still discovering problems, and plans/trips have been aborted multiple times due to unforeseen issues arising. I'm passing up the opportunity to take it wheeling tomorrow because it still hasn't earned my trust yet. I don't wanna end up stranded half-way across the state.
Two similar trucks, two drastically different outcomes. The K10 can do no wrong. But even now, the Suburban still can't quite do anything right (yet

).
If you have a good mechanical background and a solid understanding of maintenance procedures (vs. the lazy habits that most drivers follow), you may be able to spot issues before they happen. I've anticipated several (though not all) of the Suburban's issues. I would have given up in despair long ago if I had been expecting a reliable and driveable truck out of it right away. But other folks looking to buy that truck would not have seen the issues ahead of time. Those folks would probably get fed up within 6 months and think they had bought the worst truck in the world.
If you aren't good at spotting signs of shoddy maintenance, buying a vehicle is a crap-shoot. You may get a good one, or you may get a bad one. And the odds get worse and worse as the vehicles get older.