The most interesting option (danger: my dumbass opinions ahead) for why there's no other communicating species in radio range is whether there's a great filter right under our nose.

If we can ever prove that there's plenty of planets and plenty of abiogenesis and plenty of multicellular things out there that just don't know how to make radio waves, then either the leap to technology is exceedingly rare or we are in very big trouble very soon. I could see that keeping some people up at night.

Of course it could just be that, like us, other technological beings don't constantly broadcast super-directional radio transmissions at super-high power into random areas of space. We sent the Arecibo message a couple times for a few minutes, but it was really not enough to ever hope it got noticed by anyone out there. Even if space is bursting with intelligent life. Not even close. Cute project, though. Why do we expect more from others?

There was once a fairly mature plan, back in the 60s I believe, when nukes were still all the rage and people were discussing lots of exciting ways to use them for space exploration, wherein some physicist calculated how much power you'd need to make meaningful, intelligible radio contact a few stars over using an omnidirectional radio source. It involved setting off lots of nuclear bombs somewhere around Jupiter's orbit, in fact modulating the detonations and using the EMP as the signal. Those are the extreme methods needed get a signal out there up and over the noise of our own star, to defeat outrageous inverse square losses, to have it even barely intelligible at a very low baud rate a few light years away. Have we ever actually done that, even once? No.

So that should also tell you that nobody is listening to our old TV broadcasts and it's no surprise we aren't able to pick up anyone else's. No sane technological race is going to do an omnidirectional burst of communications meant for local use at such an enormous magnitude of power. It would be wasteful and destructive. Directed, focused transmissions only reach a billionth of the sky, so that has its own odds against it. SETI is a highly optimistic program considering the physics at work here.

The other argument for Fermi's paradox and why, if there are intelligent beings out there, we should know about it: If there's an advanced race even a couple million years ahead of us--just a blink of an eye in astronomical terms--they should have proliferated through the whole galaxy by now. We wouldn't be listening to their broadcasts, we would be them. Even discounting how unlikely it is that any race will ever be able to get to another star, this assumes that life (or Von Neumann machines) will spread and replicate endlessly, until they fill an extremely large space and convert an astronomically large amount of mass into themselves. We don't really see that with life we have on Earth. Most of our biome is still matter which is not life, and it's been here for billions of years. I don't understand the assumption that life will spread infinitely instead of staking out a reasonably large area that is barely manageable and then cull down, as life does here in our data set.

Even if there's a lot of technological species out there, and they're broadcasting with rational amounts of power, and they've expanded to cover rational amounts of space, it's still no surprise that we haven't found one yet. It's almost impossible to keep in mind just how big it all is. We also haven't been searching exhaustively or for a very long period of time. Would an alien SETI comparable to ours be able to detect our own transmissions? It's actually really unlikely.