WHY MY UNIVERSES AREN'T 'CROWDED'

S.E.T.I.
In many science-fiction works, the galaxy is usually cheek-to-jowl crowded with intelligent, star-faring life.

That's fine for space-opera and such, but I prefer to stick with Reality and working off it--and simply put, as far as we can tell, we're alone in the Galaxy, or as good as alone.

If other civilizations were around, and older than we are, we'd be picking up their equivalent to all the broadcast-related EM/radio frequency chatter we're blasting out. Forget 'Purposeful Contact', I'm just referring to 'overhearing' some random chatter.

Nothing. Not even traces. No distant signatures of Nuclear/Antimatter blasts either, and those are visible for a LONG ways given their EM signature and power.

UFOs
UFOs I really don't buy into as I have questions that always keep being evaded. Such as;

How is it possible with so many high-end cameras around now, that UFOs are always blurry, out-of-focus shots, and RARELY captured given the wealth of cameras around?

Why is there no real consistency in the description of crafts reported?

The abductees, they all sound like they're reading off a small group of closely-similar scripts, why is that?

''How can UFOs exist, and outright defy the Laws of Physics? I don't care if they're aliens, the Laws of Physics don't allow much flexibility, especially in terms of Gravity, Propulsion Energy Requirements, and Waste Heat.''

I'm not going to try answering these points as UFOs, at best, are something I view with suspicion. They supposedly came across Interstellar distances--for WHAT REASON & PURPOSE?? Most abductees are traumatized by their reported experiences, yet most claim the aliens are 'friendly'. Let me posit this:

Let's say a podiatrist grabs you off the street, takes you someplace, conducts medical procedures without your consent, tells you that it's all OK as he's friendly, and you come out of your induced stupor close by where he grabbed you. It wouldn't matter if all he did was massage your feet, it's still an assault, still traumatizing.

NOT the actions of anyone who is as friendly as they claim to be.

Then there's reports by abductees of being used as incubators for so-called hybrid offspring.

THE GRAVEYARD WORLDS
The reason my literary Universe isn't crowded is because Intelligent Life is vanishingly rare. Life is common, but Life that makes tools, ships, etc. is very rare.

It's very reasonable to assume that most species that make tools eventually get to the point we're at, where Nuclear, Bio, and Nanotechologies threaten us on a 3 point front, and should they slip out of our tenuous control, the results could be Extinction Level.

Out There, I posit that the last traces of radio chatter from the most recent civilization passed us by a few centuries ago, and along with such, that civilization's dying words.