What you said about the fact that we affect all other entities and it is only a matter of receptivity rather than focused broadcasting makes much sense.
It reminds me of suns and planets, how their field of gravity affects every other planet in the universe even those at a distance of infinity (although the value of their effect are similar to 0.000000000000000000000 … 00000000000001 Newton). But if the “force” that thought energy causes is stronger than the force of gravity, we could potentially even broadcast to extraterrestrial life… but surely broadcast to anyone on the face of the earth.
Now, I’d like to bring something more tangible to prove this. A while ago, I began to wonder about thoughts and what they were. Were my thoughts limited to thoughts of language? If I didn’t know language, could I still think? And talking to this with others, I soon realized that we also think in pictures and such. So I started thinking of each and every sense I had. I would imagine pictures. They would always appear in front of me and whatever I did, I could not see thought imagine behind myself unless my thought eyes were behind my body but that is cheating. Whatever you do, thought pictures are always in front of you. Thought odors are in your nose and thought tastes in your mouth. If you move your arm in your thought, you will feel it where your arm would be. Now, the interesting part. Sounds. I tried to imagine sounds and I soon realized that they all existed in my mouth. I tried hearing these thought sounds but they were all spoken thoughts. My conclusion was that any sound that is a sound, is felt in the mouth. Try this and tell me what you experience. However, in dreams, you can hear sounds in your ears and not only from your mouth. This destroyed my theory that dreams were just thoughts made very vivid because of the absence of stimuli. If dreams are not thoughts, then, they are stimuli. What causes these stimuli if not our own thoughts? They could be activated by these thought energies coming from ourselves and all other sentient beings in the universe, where mostly those that “Tune” with you are received.
Now, in practice, someone that wants to have a shared dream with another person, according to my opinions and what has been brought forward would be that:
1. The two people concerned (or more) decide on an event, a place, a thought that they all shared. For example, two friends could decide to choose a park and say they would focus on the swings. So when they would be ready to share dreams, they would have to be in that park, walk around there, especially around that swing. Also, they should choose an opinion they both had there. Let’s say they both were talking about their love for painting, and then they could think about that emotion beside the swing. Furthermore, they should imagine they were the other person in a way to create a sense of empathy and compassion.
2. These two people would have to do this exactly at the same time. This means, they would both have to be great lucid dreamers who lucid dreamed every night, in most of their dreams. Once in the dream they would have to go to the park, beside the swings, think they are the other person and think about their love for painting.
3. Most likely, it wouldn’t work because it wouldn’t be at the same time. But if they were good lucid dreamers and they did this frequently, it would most likely happen and having that experience would most likely strengthen their empathy given they would both have been in the same dream.
This seems complicated but it explains why barely anyone can ever really do it.

Just to add to all these thoughts, I cannot imagine that all DCs are actually true people because I often dream of people I know, and I know it's not actually them. So at least some DCs must be soulless... unless they are other people that take the appearance that I give them...