My first Ruger was a 10/22, built in 1974. I still have it, in it's original form, and it still shoots well. The second was a Security-Six, bought in the early 1980's. With the exception of Millet sights, and bigger grips, it's also still perking along. After that I bought a P85, a PRE Mark I, that I still shoot today.
Yet, I also own an American Rimfire in .22 WMR, a Model 77 Mk II in 7MM Rem Mag, and a set of SR9, SR9c, and SR45 pistols. NONE of them has given me any trouble.
After 32 years, I had to send my Mk. II pistol back in because the bolt stop pin had worn after tens of thousands of rounds. One week after they received it, it came back, fixed perfectly, test fired (target included), for FREE.
I also own a P89, a KP90, a P94, a KP95, a KP97, a KP345, a Super-Single-Six convertible, a GP100, one of the first Mini-14 Ranch rifles, a Model 77 pre-Mark, nine other 10/22 rifles, and a Super Blackhawk.
Surely, if the "quality had declined" as some declare, I'd have noticed.
Now, as far as returning for factory issues goes, I have had to return two brand-new S&W revolvers, a Model 625-3, and a 617. I also had to return my 669 semi-auto, and a Model 22-A. Moving along, I had to return an HK USP in .45 ACP because of a bad barrel, my Sig P229 because of a cracked slide, and I've watched S&W after S&W revolver fail a gunsmith's inspection at his shop.
Looking at one of the LGS the other day, I listened to the sales staff bemoaning the fact that S&W revolvers only seemed to cost more, but are "slapped together" any more.
I blame the rash of returned guns more on uneducated, and often new, shooters. Rarely do they seem to inspect the guns before buying them. Then, they never read the Manuals, or even clean them properly before shooting them. Of course, using the cheapest ammo they can find. Then, ANY "problems", like "it shoots to the low left" are, of course, the fault of the gun. So, back it goes, and here they come, complaining.
Every manufacturer has been trying to produce as many guns as possible, and to save a little money on each one to keep the prices competitive. Most new buyers aren't interested in perfect fits of grip to frame, or of a high luster finish. They want a gun that fits their budget, and costs as little as possible, but will shoot when they pull the trigger.
When the masses finally decided to buy guns, they influence the market much more than the guys who regard themselves as truly "gunny". The last group buy few guns in comparison.