My personal take is that there’s some kind of anthropomorphic fallacy in thinking life should tend towards “civilization”.
Life will tend towards reproductive success and it seems entirely plausible to me that reproductive success doesn’t at all imply the use of radio waves.
The dinosaurs were a very intelligent life form that never tended towards civilization and some of their bird ancestors can be smarter than most mammals etc. Expecting the trait of civilization to emerge seems unfounded and against available evidence.
Space travel seems impossible. I realize you can back of the envelope it in a way that makes it seem within grasp but there’s no economic benefit in colonizing another star and only some marginal mining benefit in even visiting the nearby planets so I don’t think it will ever happen.
After all of This Time Searching for Aliens, is it The Zoo Hypothesis or Nothing? (www.universetoday.com) angielski