Well, astronomers have found planets everywhere, so my personal opinion is that life exists everywhere too (wherever it can). But 'earthlike' will never be exactly like Earth. I'm going to bet that no two earth's are alike. Therefore no two dominant species will be alike. Which makes sense. We would like to think that all intelligent species would use mathematics, and radio transmitters, and such, and so we would be able to detect them. Based on the variety of life on earth, millions of species that we've never had first contact with, I'll also bet that no other species in the universe would use math or radio transmitters, at least not in the same way. Dogs are good at being dogs, fish are good at being fish, and humans are good at being humans. And math and radio may be uniquely human ways of doing things.

If we were intelligent crustaceans, would radio be important to us? What if it ranked low on the list of priorities? What if all math were done mentally, and mathematical relationships were obvious, or not at all important to that species? What if they had better use for the biological sciences? Or metallurgy? Or chemistry? What if we didn't care if life existed elsewhere?