Well, now I’m going to have to look it up.
To me “cur” meant less desireable or less useful, lower quality, etc. But NOT mixed breed. A cur dog, as I understood it, was a class or family of dog that was incompletely domesticated...hence the less useful/quality meaning. Cur dogs are headstrong and independent and less controllable. Very fierce in the hunt and good trackers, but worthless as a flusher, retriever, setter, etc. Poor obedience. And therefore expendable...perfect for hunting bear and boar in packs.
I always assumed cur dogs fell out of favor in the mainstream because it took a heavy hand and frequent use of a whip to keep them under control. That and the fact that they were about as expensive to purchase as a plain old yellow tabby house cat. There’s no bragging rights to owning one. A german shorthair, or english pointer commands a high dollar price and is quite a status symbol among hunters...and displays impressive obedience. Such dogs would never be put at risk chasing bear or boar.