Basically we are, aren't we?
Yes, (No? and yes.)
We are because we have not found anyone else. Should we temper that with a yet? But even if we aren’t all there is, can we even know? With our current technology, we can just barely discern the existence of other worlds where other life might exist. We could be, essentially, looking “them” right in the face and not know it.
There are so many possibilities. It could be that we are alone and always will be, or that we are simply one of the first, and all the other intelligent life is a lot like us, barely able to see out but wondering where everyone else is. Or perhaps we are late to the party and everyone else has gone into their boxes, or are hibernating and waiting for the universe to cool down so they can come out and play.
Personally, I think that a lot of the folks who do a lot of the talking about this leave out two key factors that might make contact impossible: light speed as a limit and the accelerating expansion of the universe.