> I am sure they'd get a much better response rate if they only built a single prototype that delivers whatever miniscule amount of "perpetual" energy.
Think it through:
You're given the concept of how to create free energy and you understand you can easily become a multi-billionaire (or rather: one of many, given the market size at stake).
Would you reveal your prototype before you are even sure you can serve the entire market with your production facilities?
If you do this, you would give your competitors (which is basically: the entire world) a head start. You would let them know that it works, but you would not be ready to sell. Why shoot yourself in the foot? It makes no sense. You would reveal that it works once your mass production facility is already producing at high speed.
EDIT: The logic of why it works is given transparently. If you've passed high school, you should be able to understand it.
