I don't know how much longer Diamondback at FC specifically has left, but Arrow loopers of all models are a dwindling species.
We're now at a point where ~40% of all the Arrow loopers ever built (corkscrews, loop + corkscrews, launched loops, and customs) have gone to coaster heaven.
I anticipate that over the course of this decade we'll see that figure increase to over 50% now that most of them are approaching the half-century mark.