Years ago, when the 28mm Schneider shifter came out, it was reviewed in the BJP and given a very positive rating. Its competition, in my world, was the Nikkor, and according to the reviewer, Nikon didn't quite reach the parts that Schneider could. Schneider also made other great optics for Leica: the 21mm Super Angulon was much rated in its day, too.
This thing about 'bad' copies is something for which manufacturers have only themselves to blame. In my active days I can't remember having even heard of a dud Nikkor; today, I find that even I had the misfortune to buy one such new one - that damn 2.8/24-70mm which I did manage to dispose of back to the shop, but only because I took a new 2.8/180 its place. I have hardly used the latter, despite liking longish lenses, but that's my problem and not Nikon's.
The problem goes beyond one dud lens: once you have had the bad, expensive experience, you distrust everything that comes from that maker. To lose that much goodwill is industrial suicide: how come they don't see this for themselves? Do they bank on other marques' disillusioned people changing over for more of the same, a constant turnover of angry owners drifing from one make to the other in a futile search for something that's honest? The solution/salvation is so simple: proper final inspection of every unit. From my first new F in the 60s to last year's disaster I would have sworn by Nikon; not anymore.