So, great point, there 'should' be great numbers of intelligent 'systems', yet we don't detect them. Why? It's the basis of Fermi's Paradox,
which is roughly as follows.
"The size and age of the universe suggest that many technologically advanced extraterrestrial civilizations ought to exist. However, this belief
seems logically inconsistent with the lack of observational evidence to support it. Either the initial assumption is incorrect and technologically
advanced intelligent life is much rarer than believed, current observations are incomplete and human beings have not detected other civilizations yet,
or search methodologies are flawed and incorrect indicators are being sought."
So with all of that, he gives basically 2 possibilities. Either there are none, which seems so very unlikely, or we have yet to detect them, even
though rationally it would seem there would be so very many, to the point of being impossible to miss.
And so the paradox is that the latter seems very much more likely, but evidence contradicts it.
Personally, I would also find the second possibility far more plausible. They are there, but we have not detected them. If you disagree, ok, I can
accept that, be a skeptic if you like, as I don't think anyone really knows, we are operating almost beyond a point of what science and statistics
can predict, as the uncertainty of the Drake Equation illustrates. But there are strong reasons to believe they should be out there. Many people, I
would say most people who seriously consider these issues think they are there. Not that that makes it true, but that is the prevailing wisdom.
Now, if you use the presumption that they are there, why can we not detect them? This is where it gets more interesting. The answer has to be one of
the following, we haven't looked hard enough, we have a flawed or inadequate detection method, or we are simply incapable of detecting them as they
are simply undetectable. Or any mixture of those things.
Here is my opinion. It is a mixture of those three things. Very many intelligences have evolved and are evolving, and many many have evolved similar
to ours. Some are radically different, and we simply wouldn't recognize them. Also, many like ours have evolved to the point of radiating signals
all through space, yet we don't see any, why? And here is the answer to that. They do not do that for very long! Soon after reaching an
intelligence that allows them to send such signals, if that is the path they have taken, they will soon stop doing that, or we would see them
Why? When an intelligence reaches a certain point, which is not far from the point where the current human species is, it is very close to the end of
it's existence in that form. That intelligence is highly unstable. That would explain why we don't see other intelligence in the universe. As
soon as something gets intelligent enough to make its presence felt in the universe, it is shortly gone thereafter.
And where does it go? There are 2 possibilities. It can either destroy itself...
Or it 'transcends' the current state of existence, to
something far beyond what we can detect or understand. In other words, it basically just evolves out of existence. Or if you like, you can use the
terms of the OP, such as "move through time" or "to another dimension". Some futurists will call it the "Singularity". The intelligence
becomes intelligent enough to evolve itself at massive rates, and become something radically different. At any rate, it's all the same to us, as we
have no idea where they go, it is beyond what we understand, and they are just gone as far as we are concerned.
I think this is what the OP is getting at, and I agree with him. John Smart wrote an excellent piece concerning the Fermi Paradox, read it here, and
see what you think.