Has there been a calamity in the supply of Arabica? Used to bry the house brand of WalMart, which was labeled "100 percent Arabica". Now it only says "100 percent coffee". The taste is shot. Bought a Don Pedro brand labeled Arabica; it was good, but now can't find it. Checking other brands fails to find a 100 % Arabica. Can you shed any light on this?
Good question. The simple answer to your question can be seen in this chart.
The text is a little small, but basically, you can see how the price of Arabica coffee beans has risen a great deal between 2006 and today.
It used to be that supermarket coffees boasted they were 100% Arabica, and pretty much all gourmet coffees still are.
But faced with this huge price increase, the supermarket coffee distributers have had to replace some of their Arabica beans with Robusta coffee beans.
In other words, to keep the price of their products at a reasonable level, they have been changing their blends to include more of the less expensive Robusta beans.
The trouble is, as you say, people can taste the difference and are not happy!