The only economic reason for extraterrestrial invasion would be for permanent colonization. There would not be another.

Not that everything need be governed by economics, of course. Weird alien religions might be at play.

But the most likely reason we’d be invaded from without is for colonization after some civilization has destroyed their home world — as we will likely do to ours. Fortunately for any habitable planets out there, we have no starfaring capabilities nor are we likely to develop any within the next 500 years.

Rest easy, though — the fact there is no archaeological evidence of past invasions implies the probability of that occurring is extremely low. It is not a real risk.

But it is more fun to think about than the fact that we are far, far more likely to do all the hard work of extinction and extermination of ourselves to ourselves.

Maybe the aliens are just letting that play out.