Right, I’m with you there. We’re talking the difference between something being possible and being probable.
I’m not saying probable, just that there’s a chance. It lessens every day, but it will be a good while before it’s zero.
And it’s absolutely correct that we’re looking for something in an unsophisticated way.
We assume things progress like they did here. Big picture, maybe. The devil’s in the details, and depends when a civilization discovers different things. Maybe a civilization finds a better way to transmit than radio, thus never produce radio waves. It could be anything, but that’s an easy example.
But considering possibilities, there would be places out there that did get radio. But now you have to wonder if they could be close enough to detect. If the closest civilization that discovered radio, and also let it fly out into space, is 3 galaxies away, the we’d probably never detect it.
And absolutely true that a civilization or many could pass by here and we’d never detect the signature, as it uses something we won’t know about for 800 more years.
Really is kind of fun to think over.
*takeItUpWithAutoCorrect