The technology is there but your government hides it. All these things people say we need to fix can be fixed by branching out and starting new worlds.
Most "government hides it" is proven to be false once the paper trails are cleared of confidence but, like any rumor, they take on their own life.
Mars is the closest we got and the six months it takes to get there right now presents too many problems we can't overcome yet (namely, transporting enough food and water); nevermind the nearest star which is some 5 light years away. It would take an army of robots years to prepare Mars for human arrival at an astronomical cost no one is willing to pay especially when the only benefit of going there is to get people of Earth (there's little in the way value there--water being the most valuable commodity).
And the conspiracy's begin....
I only do F@H. I feel that it's the only one i can contribute to wisely. I would crunch, but this is my main rig and is a server for the family. I would "SETI", but i'd rather help disease than send some nerd to confront an Alien.
Which might just eat him and find more tasty treats from where the nerd originated...
I have to assume that any species that has reached space are as vicious as we are. They will look at everything, just as we do, through an "how do I benefit" lens. There's craploads of water on this planet that, alone, is reason enough to extinct humans. ET can stay away as far as I'm concerned. We don't need another war with a race that has technology far superior to our own.
Let me put things in another perspective...
It took Earth 4.7 billion years to get where it is today. It took humans millions of years to get to where we are today. If there is another species out there that is on the same path we are, they most likely haven't existed long enough to make their planet an electromagnetic light bulb like we did and have it
exist long enough to reach Earth. As such, the species could be there, right now, but we won't know about it for thousands, if not millions, of years longer.
In the end, I think it is overly optimistic to believe another species is running around being a saint to every lowly species they find. That isn't realistic at all. I mean, if we found a planet like Earth in a nearby star, we get there to discover there is a species much like our own but only evolved to the level of a chimp, how likely is it that we treat them like animals and steal all their oil? I say pretty likely.
Humans are so selfish and I have to assume any species equal or greater than humans are at least equally selfish.
Anyway, enough banter/theorizing from me.