Bayesian reasoning applies here. Natural phenomenon is the most likely cause.
think of it this way: imagine in the future we travel to Alpha Centauri and find sentient life or even the remnants of such. That would be really bad. Why? Because if there are 2 civilizations in our galaxy, how likely is it that they're next to each other? Incredibly unlikely. It heavily implies that sentient life is much more common. Now imagine if we find a third at, say, Barnard's Star.
In Fermi Paradox terms this heavily implies that there is a Great Filter ahead of us and we're more likely doomed than not.
Finding a Dyson Swarm near us has the same negative implications (for us), especially given that the gap between a partial or full Dyson Swarm and colonizing the galaxy is relatively small (~100 million yaers) in cosmic terms so how likely is it that we find a Dyson Swarm that is a) near us and b) in that narrow window between the emergence of spacefaring life and colonizing the galaxy.
That doesn't track. The fermi paradox is "we don't see evidence of intelligent aliens, even though we expect them to be abundant" and the great filter concept is merely an argument for why they would not be abundant.
If we find abundant evidence of intelligent life, there is no fermi paradox, and thus there would be no reason to explain life's fictional rarity. The answer to "where are they?" is "right over there."
think of it this way: imagine in the future we travel to Alpha Centauri and find sentient life or even the remnants of such. That would be really bad. Why? Because if there are 2 civilizations in our galaxy, how likely is it that they're next to each other? Incredibly unlikely. It heavily implies that sentient life is much more common. Now imagine if we find a third at, say, Barnard's Star.
In Fermi Paradox terms this heavily implies that there is a Great Filter ahead of us and we're more likely doomed than not.
Finding a Dyson Swarm near us has the same negative implications (for us), especially given that the gap between a partial or full Dyson Swarm and colonizing the galaxy is relatively small (~100 million yaers) in cosmic terms so how likely is it that we find a Dyson Swarm that is a) near us and b) in that narrow window between the emergence of spacefaring life and colonizing the galaxy.