Indeed, it was gone, and... I don't know, but I guess it still is. The Single-8 film is not sold in Fuji boxes or even in Fuji cartridges, so it could very well be old stock, spooled into the cartridges by another company.
I've also read about a possible come-back. "it is not completely excluded that Astia 100F might come back one time" (see
this thread). That sounds rather iffy, so it's safe to assume that the Single-8 is old stock Astia.
Hm... which slide film are you using now? Will that be the next one to go?... :whistling: