If many people currently rely on breaking and repairing windows for their livelihood, a “stop breaking windows” type law has real negative consequences, unfortunately.
I think a potential motivation for investing in megascale engineering projects is right there in your comment — military advantage. If humans do manage to colonize other planets it seems inevitable that there will eventually be wars (cold or otherwise) that involve many billions or trillions of people spread over multiple planets or star systems. An ongoing conflict on that scale seems like a great reason to develop a Dyson swarm — we don’t know what kinds of weapons would be involved in a war like that but it’s a safe bet that they require enormous amounts of energy. The first Dyson swarm may well be the result of a dick-waving contest with mass drivers instead of ICBMs.
Just think, a military entity with the population and resources of NATO or the Warsaw Pact would have been totally inconceivable just a few hundred years ago.
The problem is, a civilization with the kind of industrial base and know-how to build Dyson swarms, if it was still interested in 'military dick waving', would be trivially capable of knocking everybody back into the stone age, or even, totally rendering every planet with a biosphere uninhabitable.
Worse, in such a civilization, it's pretty likely that even small organizations would have the kind of tech you'd need to induce a nuclear winter on a given planet. After all, you just have to crash an asteroid on the right spot, then you have a mass extinction that human civilization would definitely not survive.
Great (and terrifying) point. In that light it would seem that the major blocker for these types of engineering projects isn’t technological advancement as much as advancement in governance/social organization/psychology.
Let's not forget about the crazy either. Both those with mental illnesses making them destructive, and those mutilated by the system. Think of the occasional random people going on shooting sprees or bombing runs. Imagine them with access to a home pathogen lab, in 20 years.
The major blocker full-stop. Adorno once used the V2 flying bomb as a metaphor for our society: as the marriage of total technical brilliance with utter futility and idiocy. I think it's frankly surprising that we didn't blow ourselves up in the cold war. We're extremely developed as technical thinkers, but as social thinkers, half of us vote Trump, and the other half don't have the words to express why that's awful.
A civilization with the kind of industrial base and know-how to build Dyson swarms probably also has the ability to create smallish self-sustaining colonies, in space or on/within uninhabitable planets. With enough of those floating around, even if most of civilization was wiped out, it seems likely that someone, somewhere would survive... and potentially be able to reseed a future civilization. So there’s hope.
Culture wars aside, the premise seems reasonable though, doesn't it? Intraspecies reproductive fitness is orthogonal to species success and there are clearly some examples (e.g. brightly colored plumage) where a trait that improves individual reproductive success is a net negative for the species.
Traits don't evolve in isolation though: the need for costly signaling may very well select for increased generalized fitness as a way to "pay" for the signaling.
Bright plumage can advertise "Look at me! I'm fast enough to look this amazing and not get eaten!" For this strategy to work, you need to actually be fast.
Is it a net negative though? I would in fact wager the opposite. The tradeoff must be beneficial else natural selection would have culled them from the population.
I believe in this specific case, it is likely more difficult for males to attract females than avoid predators.
To start off, yes, the trait needs to provide a reproductive fitness benefit. The problem is runaway sexual selection [1]. The textbook example of that being the peacock plumage, which is subject to strong sexual selection, yet is a detriment to overall fitness (see link for more details).
