But that's not what happens: proposed alien technology always approximately tracks human technological development. I'm having trouble finding it at the moment

But that's not what happens: proposed alien technology always approximately tracks human technological development. I'm having trouble finding it at the moment, but somewhere out there is a pretty good article that points out that even though more people are now carrying cameras than ever before, UFO sightings have basically fallen off a cliff. They rose with the advent of jet aircraft and the space age, and then fell away in the era of drones. (The ones that I found in search results weren't the one I was thinking of.) "Lightsail" is being floated as a possible explanation for this because we've recently imagined that technology. A few decades earlier, and nobody would imagine it as an explanation; a few decades later, and we'll have some other favorite new possible explanation that we can't imagine now. The article wasn't terrible, though.