Wanderport Corp (WDRP)

[gharma]

Thank you for clarifying, as that is exactly what I meant, that I feel Robert has made something (a device) that can heat water. You or I could also if we wanted to junk our microwave oven, coat some parts in hardware store purchased rubberizing, and immerse the result in a tank of water with an inlet and outlet, all surrounded in some shielding (which is possibly not so necessary as given sufficient surrounding water there would be little ambient microwave radiation to present a danger).
I do feel Robert has something that heats water. It appears that it is not too reliable, or not well tuned.

Of the 4 options you present my inclination is close to your number 3, which was stated as

3. They have something that technically heats water but is very inefficient. I would say this is the most likely scenario at this point unfortunately, at least the one that best matches their behavior.

but which I would modify to
3b. They have something that technically heats water efficiently but it is no more efficient that existing products while being significantly more expensive than existing products.