This is so true. A mentor of mine has been developing a new cancer therapy with a physicist for over a decade. He's spent millions of dollars and all he has to

This is so true. A mentor of mine has been developing a new cancer therapy with a physicist for over a decade. He's spent millions of dollars and all he has to show for it at this point is a machine for rats that can kill cancer better than the standard of care, for rats. He's building a machine for humans now but by the time he's done he'll have probably invested close to $10M all by himself just to have a single proof of concept that he can take to market. That's an insane amount of investment until as you said, you even get to the point where you can get real feedback on the business model. Ultimately though he understood the fundamental physics and knew that it would work just as well as anyone could.