"They have a mat of messy protein extrusions in place of an exoskeleton, their eyes have no facets, and their thorax is completely indistinct from their abdomen!"
- Insect Aesthetician
While I subjectively agree about cats, "aesthetically well put together" is downstream of the "evolved innate" factors.
Beauty is objective. Taste is subjective. Hence why we can say that someone has poor taste, i.e., the subjective fails to align with the objective.
I can admire the beauty of an insect as an insect without me being an insect. Similarly, if an insect were intelligent, possessed with an intellect, it could judge the feline as a beautiful creature as a feline.
"As X" is important, because it is a matter of how well the specimen realizes the telos of its species. Hence, why defect is ugly. You wouldn't say pi is an ugly integer. You wouldn't say a hammer is a crappy saw. You wouldn't say a fish is a bad mountain hiker, except as a shorthand for "fish do not mountain hike, are not anatomically + physiologically ordered toward hiking".
And of course there degrees of good, and therefore, beauty, based on how much more you resemble the Highest Good and therefore the Most Beautiful, Goodness and Beauty as such.
I would say that the cute cats are domesticated species, like many animals. So they wouldn't exist without humans, and it's in their benefit to behave to survive.
Compare this with dogs that are more of a "working animal." We've bread dogs to fill specific roles because they were larger to work with. If humanity had tried to find companionship in the mountain lion instead of Felis lybica (the wild cat).
Also for the how almost-domestic the African wild cats are: https://youtu.be/ZRqlSr1Yp1M
The other part of it (as I understand it) is that cats body form is not as easily selected for when compared to animals that humans have domesticated.
Dogs have a number of body sizes that can be "easily" selected for - https://embarkvet.com/products/dog-traits/traits-list/#body-... and https://embarkvet.com/products/dog-traits/traits-list/#other... (there's even a mutation of https://en.wikipedia.org/wiki/EPAS1 in wolves that was selectively bred into dogs https://academic.oup.com/mbe/article/34/3/734/2843179 )
I suspect part of the lack of range comes also from that the cats of size that don't eat us are not ones that can be crossbred with cats in the wild to introduce new useful genes. Trying to cross a domestic cat a wild cat doesn't produce a new cat that is useful in a new role ( https://en.wikipedia.org/wiki/Felid_hybrids#Confirmed_domest... ). Compare this with domestic dogs and the various wild dog species.
The 14 genes mentioned that control dog size: https://research.nhgri.nih.gov/dog_genome/study_descriptions...
The concept behind this is https://en.wikipedia.org/wiki/Phenotypic_plasticity
And linking to a reddit post about this from a while back - https://www.reddit.com/r/askscience/comments/1hhzcn/why_do_w...
Elevated basal slippage mutation rates among the Canidae - https://pubmed.ncbi.nlm.nih.gov/17437958/
> The remarkable responsiveness of dog morphology to selection is a testament to the mutability of mammals. The genetic sources of this morphological variation are largely unknown, but some portion is due to tandem repeat length variation in genes involved in development. Previous analysis of tandem repeats in coding regions of developmental genes revealed fewer interruptions in repeat sequences in dogs than in the orthologous repeats in humans, as well as higher levels of polymorphism, but the fragmentary nature of the available dog genome sequence thwarted attempts to distinguish between locus-specific and genome-wide origins of this disparity. Using whole-genome analyses of the human and recently completed dog genomes, we show that dogs possess a genome-wide increase in the basal germ-line slippage mutation rate. Building on the approach that gave rise to the initial observation in dogs, we sequenced 55 coding repeat regions in 42 species representing 10 major carnivore clades and found that a genome-wide elevated slippage mutation rate is a derived character shared by diverse wild canids, distinguishing them from other Carnivora. A similarly heightened slippage profile was also detected in rodents, another taxon exhibiting high diversity and rapid evolvability. The correlation of enhanced slippage rates with major evolutionary radiations suggests that the possession of a "slippery" genome may bestow on some taxa greater potential for rapid evolutionary change.
(and if you're interested in genetic diversity and fossil records, https://en.wikipedia.org/wiki/Cat_gap )
Arthropods and even snakes are morphologically too distant for that. Nevertheless, people usually find large-eyed geckos more cute than armor-eyed chameleons or tiny-eyed crocodiles.