I still wonder if we're barking up the wrong trees.
Maybe the assumptions we're making about advanced communication are like a primitive aborigine assuming that advanced civilizations would communicate across oceans with mountain-sized drums.
The IR radiation that any large-scale use of energy has to release isn't going to be easily observable near stars.
What else would be a signpost that would be the same regardless of level of technology? I'm thinking of things that are side effects, not deliberate attempts to make contact.
It's possible that nobody is broadcasting across interstellar space on purpose for the same reason that people swimming in shark-infested waters try not to do a lot of splashing.