(edit)^oh wow, so I didn't effectively communicate either point (acknowledging I was OT, & that I was the one coming from that "remember when everything was a nickel" perspective)!
Okay more on topic, I haven't eaten there in a while, but a few years ago taco bell had a grilled/stuffed burrito that had a chipotle sauce they couldn't keep in stock- there was much borrowing among locations of it just so everyone could make it, and they often couldn't.
So given that you'd assume it was popular enough to justify keeping around, but they discontinued it shortly after.
Someone correct me if it's since returned.
I'll go back for that one.