I think intelligence is like flight - an ecological niche independently explored by multiple different species. There's no manifest destiny pushing in that direction, but just as I expect other planets with complex animals will have some that fly, I think it will have some with varying levels of intelligence. Given enough time, some will reach or surpass our level, and they have a lot of time.
People keep forgetting that Earth has at least another 500 million years before it turns into Venus, maybe longer. That's a lot of time for other pretty intelligent species to keep getting smarter, and the same thing can happen on other planets. Being stagnant for a million years is a blink of an eye, not something to worry about from an evolutionary perspective.
Space/Science » in reply to A Related Note On Rare Intelligence
intelligence exploited by multiple species on earth