Eh, as far as plants go I guess it depends how you define domestication. I'm not a plant person myself, so I haven't given it as much thought. I dunno. There are definitely some changes we've made to some plant species that would be seriously impractical for them in the wild.

You're probably right about the survivability of cats vs dogs on the whole, although domestic cats are still pretty dependent compared to wild animals, and of course it depends on the kind of dog. A lot (though certainly not all) of the more extreme dog breeds were originally bred that way for some specialized purpose, and some of them got... uh... interesting as the practical context faded away. Dog breeds have their own trends in behavior and intelligence too, though. That's also an important ingredient in survivability, especially since they are socially dependent animals at heart.

Cats, on the other hand... their traditional role as vermin-catchers doesn't really require social interaction as such. It's just more effective for everyone involved if they can stand living in a close space with humans and each other. Compared to dogs, though, their relationship with us is nowhere near as integral. I wonder where along the line people started making friends with 'em.