No way we're the most intelligent life form in the universe.
I was thinking about this very thing a couple days ago, coincidentally. Consider the difference in intelligence between us and the next most intelligent species on the planet. I dunno if that's still considered Dolphins or what, but whatever. Imagine all humanity has accomplished, uncovering the secrets of the universe. Then just imagine a species developed that's just the same difference between us as we are between dolphins. And that's small potatoes. Who can imagine just what limits there are to intelligence in biological creatures. Lord knows this godawful species isn't the limit.
Likewise, and this is totally separate from that, but I don't buy the we haven't made contact, so they are either too far or don't exist. First and foremost, they wouldn't communicate with radio waves. We just proved Neutrinos can be used to communicate, and heaven only knows it'd take a far smarter person to explain or imagine how quantum entanglement could be used if it can be mastered, but seems to me if it could, the limits are endless. And I personally think we haven't scraped the surface. There's a level below quarks and muons and all that jazz, just as matter is made of molecules made of atoms made of muons and all sorts of matter. I don't buy there's an end to it. Then we admit we have no clue what 90+ % of the universe is, could be, or even if it exists.. Then considered said believers in ghosts, our countless wars, etc. If there were a more advanced species, let's face it, if they make contact, would it definitely be net positive? Or is there an overwhelming chance people go apecrap, countries fight for technology, and religions fight for existence? If they are out there, the fact they haven't made contact only proves they are smarter than us. Which isn't hard to imagine.