"It's very rare for cartridges to just die. I still have folks asking for .38 S&W and .32 S&W Long enough to keep those loads in stock. As long as there are guns, there will be demand for the ammunition."
I will throw a big "AMEN!" to that one. Just browse the available brass at Midwayusa or Starline. I venture to guess that if it was a commercially produced cartridge in the 20th century, it's probably available.