The search for Dyson Spheres continues for some unknown reason.
I always thought the idea of trying to detect a Dyson Sphere was ridiculous… first off there is no reason to believe they even exist anywhere or would be a forgone development point for any civilization… “okay, we have the ability to bend space and time. What’s next, oh yeah, let’s encase our sun totally, harvesting its energy completely.”
Secondly, and more importantly, if you have the ability to encase your sun (or even a galaxy- as the thinking goes)– wouldn’t it stand to reason that you probably also have the ability to hide this monstrosity from distant observers.
Thirdly… I have never seen it in the tech tree for Civilization… so I call shenanigans.