There is a Walmart-Mexico near Ajijic. They had the best pork tenderloin, a cut not offered in any of our Mexican butcher shops. I bought it weekly for at least 6 months. Then, voila! they disappeared. I asked el jefe at the meat department, porque no mas? He spoke English and said, "Senora, it was so popular I could not keep enough in stock to please everyone. So I stopped ordering it."
I was told the same thing at a local papeleria, where I had been buying bubble-wrap (not a common item). I think it's almost endearing; instead of disappointing customers because they run out of items, they simply stop carrying the item??
But then again, I have been accused of being a Pollyanna.