They still have them, and they are a reasonable substitute for American hotdogs, but as posted above, IMO, Villa Market at Sukhumvit Soi 33 has the best selection of all actual American imports, albeit on a hit and miss basis.
FWIW, I buy a lot of stuff online from "BritiShop, Expat food delivery Nationwide across Thailand" . They have a great selection, quick delivery, and found some excellent sausages that are identical to American breakfast sausage. There meat pies great. Personally, I find their prices reasonable, but I suspect many here will bash the prices as they do everything else.
BTW, I am an American that's been here for nearly 30 years.