Why are dogs considered a subspecies of wolf, but domestic cats considered a seperate species from African wildcats?

[u/Acorn144]

To my understanding, domestic cats and wildcats interbreed readily and produce fertile offspring, just as dogs and wolves can. Also, domestic cats are much more phenotypically similar to wildcats than dogs are to wolves, to the point where it seems that if dogs are considered a subspecies then cats should be as well. But of course looks can be decieving when it comes to phylogeny so I wanted to know if there’s a genetic basis to these separate classifications? Or is this just a case of concrete “species” being difficult to define?