I don't know when it will happen--hopefully within our lifetimes--but we will find intelligent life on other planets, whether they are more or less advanced than us. It will be one of the greatest days in human history to know for a fact that we are not alone in the cosmos.
I think that we will eventually find life on another planet, because if you think about it there is an infinite number of planets, or at least we think their are, so we are most likely not the only planet that has life on it. There is probably more out there.
First, I think you have to judge what intelligent life is. If we find a rat type creature on another planet, that's good enough for me. Its not a single cell organism, thus making it in my parameters for a Martian. If you think we are going to find little green men in saucers, its probably not going to happen anytime soon. It depends if we expand or cease to exist in the next million years. We will eventually get out of this solar system.
The idea of life "up there" is a manifestation of the long defunct "space age". Decades of astronomical research, And decades of SETI searching tens of billions of radio channels has not revealed the least evidence of life in space. Looks like we are alone after all.
But lets do a little thought experiment. Suppose there is a boogie man at some star out there. Since there are about as many grains of sand in the world as there are stars in the universe, Finding said boogie man is like finding that elusive sand grain with tonight's lottery numbers engraved on it by the forces of wind and water. Ie so close to zero that for all intents and purposes it does not exist.
As for intelligent life? What is that supposed to mean? What is the intelligence scale anyway, Where do us humans fit on it, And what does it matter anyway if there is nothing else to apply it to?
All the exoplanets that we're finding are tens to thousands of light years away. If this were a problem which can be overcome the odds are that some other civilization with a billion year head start on us would have reached out and tapped us on the shoulder by now.
While I am open to the idea that there is other intelligent life out there, I believe it is too far away for us to ever actually encounter. The more likely scenario is that we find simple organisms on another planet, but even that is unlikely to happen for many more years.
No, humanity will not find intelligent life on other planets. While the universe is most certainly big enough that there is likely intelligent life somewhere out there, as sad as it may be, it is also so big that it makes it night impossible that humanity will ever find intelligent life outside of Earth.