Something that I think keeps getting missed is that much of modern dog training labels a dog "smart" when what they should label it as is "biddable" or "easy to teach with current methods" or "not easily discouraged".
I find many sighthounds ARE smart. But they are smart in ways that are useless to the way we keep dogs in our culture, so we regard them as stupid instead because we cannot use their intelligence in the way it manifests. A dog that makes an association quickly and adjusts its behavior accordingly- whether to avoid a thing it didn't like or to continue to get the thing it did like- is a dog that survives very well when out of human hands because it learns "thing bad no likey" instantly and doesn't need multiple lessons. Unfortunately that dog is also way harder to convince "hey thing isn't actually bad" because single-event learning is the bane of modern dog training and you'll see all the modern dog trainer hotshots complaining about the pitfalls of single-event-learning.
Modern dog training often makes use of drilling- whether it says it does or not- which is great for a dog that doesn't become discouraged easily and that genuinely wants to work with you to puzzle through it together. It's no wonder that we consider dogs that do well in this environment "smart" and does that think this environment sucks "stupid". I've talked before how Sushi really doesn't like drilling but she also picks things up incredibly quickly, becoming reliable after just a few positive reps. Not surprising in a breed that had to learn quickly on its feet or risk falling off a mountain. So does that make her smart or stupid? I think it shows her intelligence that she can learn something within just a few tries, even if her performance seriously backslides if I push her past that point.
However I also joke that Sushi is not very smart. Not because she's hard to train, she's ridiculously easy to train. I think she's smart enough to train well but not smart enough to question my word, not smart enough to push boundaries, not smart enough to get herself into trouble on purpose. She's smart enough to learn the rules but not smart enough to ask why those rules are in place.
Many dogs who people don't consider smart (LGDs, sighthounds, independant-hunting hounds, terriers, spitzes) are actually super smart, smarter imo than breeds easier to train. Their brains just don't work in the way that modern dog training wants to work the dog. Why should they puzzle through a hard task with you? They're very okay doing it themselves, by themselves, thank you very much. These are often dogs that learn how to open doors, climb over fences, pry open food containers, knock out screens in windows, and more in pursuit of what they want. Sit for a cookie? Why should they? They can just get it out of the cookie jar themselves.
Tldr a lot of modernized dog training, at least in western and European countries, mistakes "trainable using these methods" as "smart", and because cookie cutter training is all the rage no matter what side you sit on in the Methods Debate, you'll run into problems with that once you get a dog that needs a bit more creativity in the actual application of training instead of focusing purely on the method of which one trains.
But dogs were not domesticated to work with us in such a specialized manner. They were domesticated to exist alongside us, to help when we needed it with things like hunting or guarding, and then mostly to fuck off and do their own thing until we needed them again. Nowadays we ask dogs to wait on our every beck and call and thus both breeding priorities and training methods have undergone several drastic changes in the mean time. And you'll notice breeds and types still expected to fuck off until they're needed again are the ones people label "stupid".
