I believe human-level general intelligence (and beyond) is already inevitable, even if we don't make significant developments in "solving" intelligence. Projects that are already developing stuff like this (e.g. IBM Blue Brain) are just copying the human brain as closely as possible. Of course, this isn't as efficient as it could be (they simulate it all at the molecular level, so you can only get 1 neuron per CPU). However, as Moore's Law progresses, even if we don't make the software more efficient, we will eventually be able to create a fully functional simulation.

But if you look at the history of technology, things we create aren't usually exactly based on models seen in nature. Airplanes aren't exactly like birds. I believe we will find a more "man made" model for general intelligence (maybe not even a neuronal model) that works much more efficiently with the hardware we have available.

Going back to the airplane analogy, we already have the people who strap wooden wings to their arms and jump off buildings (like Blue Brain), but we are looking for the first Wright brothers design.