It's fascinating that supposedly rational skeptics here are entertaining a wider and wilder web of conspiracy theory involving an increasing number of people in an increasingly fantastical scam over time.
You've raised an excellent point! Let's take a look closer. For grand conspiracies such as the moon landing, this is an important criticism because when you add everything up it's simply not plausible. So what about this one?
Here's the question: Is the number of people involved that would have to know it's a scam so large that paying them would require more money than the conspirators have?
For the moon landing, the answer was yes. Faking it would have involved so many people that the whole thing just falls apart. But for this one? I don't think it's an issue. You have the normal number of con artists for a free energy scam, and then as it gets more money and drags on longer you add some more staff - some of which are directly in on it, some probably know but not officially and are just apathetic, and some may be true believers. Then you pay a few actual scientists to say it's legit.
This is all in line with other scams, and would still allow them to operate at a profit.
So that's the 'number of people' part. You also said the scam was "wild" and "fantastical" and so for that part we would need to look at the core claims:
For this to be a conspiracy in the way that has been described, the following would need to be true:
1. Someone is greedy and willing to lie, and can find people to work with him - many of which would also need to be greedy and willing to lie. (So far so good, these people are not in short supply.)
2. That person would need to make up a free energy device that sounds sciency but isn't real. (This happens all the time.)
3. That person would then need to offer up a string of excuses and explanations that would allow them to keep collecting investment money without producing a marketable product. (Nothing wild or fantastical about that.)
4. They would then have to find scientists willing to say the tech is legit. This is really a sub-set of point one above. (Still not a problem, scientists are people too and often underpaid at that.)
That's really it. None of that is wild or fantastical. Now think about what would need to be true for this to NOT be a conspiracy...