Probably the era before you were old enough to drive from your response. I am not quoting JDPowers or Consumer Reports or any other internet claim. PM26 is correct in my general opinion, except I can't say that Korean parts are any better. I base my observations on my personal experiences. So I guess that the 1994 Impala SS that I bought new and kept for 21 years that NEVER went back in the shop and only had oil changes and 1 tail light bulb go out was poor quality from Arlington Tx using mostly American parts. Or maybe the 1995 Silverado that had nothing but oil changes and a set of brake pads. How about the 1982 Silverado that only had normal maintenance for that era of vehicle? Had a 1976 Caprice that was kept for 18 years that never had anything other than wear items replaced. Or we could fast forward to the 2005 Grand Prix that had an alternator, and about 10 window regulators (import crap from Mexico and China), radio, weather stripping, blower motor, blower relay, the steering wheel get that gummy crap oozing, transmission switch/solenoid and other issues that I can't think of right now. Just to be fair, I put 220K on the 76 Caprice, 190K on the 82 Silverado, 280K on the 95 Silverado, 58K on the 94 SS and 115K on the Grand Prix.
Currently still have the 2001 GMC and the only real issue with it has been pinion bearings failing until I had it rebuilt out of warranty. Used good bearings and no more trouble. It only has 308K on it and the motor has never had a valve cover off, original transmission, and just had the AC compressor replaced.
So claiming that quality is getting better is painting with a very broad brush. To say that China made parts are just as good is just talk. Come back in 15 years and lets see how well they held up.
Getting back on topic, crap does break, but AC compressors should last at least 100K miles if not more. Of all my vehicles, the 01 Sierra is the only one I have ever lost a compressor, and it was the clutch that failed, not the internals.