"just as many"? Press X to doubt. I don't doubt you've heard some, but people just don't care about cat breeds in the same way people care about dog breeds.
I had a cat that was not an asshole. But he was severely disabled. Bad brain damage, nearly blind, digestive issues, and a heart murmur that turned into heart failure.
Lil dude was too dumb and fragile to be anything but the best cat in the world. The only thing he did that annoyed me, was stealing slices of pizza, eating the cheese off of them, then putting the soggy slice where he knew I'd step on it. It was too funny for me to be actually mad.
He had a great 8 years and knew nothing but complete adoration from literally everyone he met.
There is a cat fancy, purebred cats exist, but there is a population of normal cats in the world that haven't had their genes mangled, where there really isn't with dogs. Every single dog in the world is a something something mix, whereas my cat is "a grey one."
It might be more to do with dogs having a very high degree of genetic plasticity, unusually so. I remember an interesting paper on it. This just doesn't seem to be the case with cats.