I think the hypothesis that we're not listening to the right things makes the most sense. Radio isn't efficient and unless highly boosted doesn't really work at a distance useful to interstellar civilization. At best, you'd be able to do a local broadcast to the next stars, so about like expecting a modern company to conduct business via pony express. There are no ponies, so obviously national chain companies don't exist. Amazon has no ponies.
I think the hypothesis that we're not listening to the right things makes the most sense. Radio isn't efficient and unless highly boosted doesn't really work at a distance useful to interstellar civilization. At best, you'd be able to do a local broadcast to the next stars, so about like expecting a modern company to conduct business via pony express. There are no ponies, so obviously national chain companies don't exist. Amazon has no ponies.