Ie, what humans view as "intelligence" isn't actually an emergent property of the right set of rules. Rather, it's a massive and hopelessly self-intersecting set of ad-hoc solutions and special casing all jumbled together over millions of years of evolution, producing something that looks general, but only because we're looking at it from within itself. An easy example: Having a computer identify all images of a thing called a "cup". That's an arbitrary category that has no definition reducible to actual physical properties. What makes something a "cup"? A human saying it is one.
For something to look like "full, general AI" to humans, we'd need to either: Build something that replicates all that specialized hyper-meta-spaghetti-code mental processing of ours to a level of fidelity that's beyond both our current understanding of our brain's structure and the level of complexity tenable by human computer science. Or leave out those evolutionarily-discovered "optimization circuits" and require far, far more processing power than we'll have access to for a good, long time.