What Happened to Ham in Restaurants?

One of my favorite restaurants in the world is Jack Stack Bar-B-Que in Kansas City. I've been eating there since my father used to purchase their "49er" sandwich (called the Jack Stack Sandwich before it was discontinued) in 1957 when it was on Troost. It was brisket, ham, lettuce and their sauce on a delicious roll. During the last few months when I have ordered it, I was told it was discontinued. Now, I've learned the restaurant no longer serves ham -- at all. 

We came back from KC today and it was the first time I can remember not visiting. Without ham, I'm not as interested. 

On the way back from KC, I went into Arby's, ordered their ham sandwich, and was told they no longer serve ham (I guess they no longer have "the meats"). 

So, I did a little internet research and found the following no longer serve ham:

• Panera.
• Subway (UK).
• Hog Wild Bar-B-Que (Wichita, my home)

What's going on? What happened to ham?

Any one know what is behind this? Please let me know. 

Meanwhile, I probably will not go to delis or bar-b-que places that don't serve ham.