So you've only looked at the very loud people talking about this, and not the hundreds of quiet people working on this?
How many smart people worked quietly at Theranos, knowing that a drop sample from a thumb was incapable of carrying sufficient blood volume for a legitimate sample, but thought "hey, maybe someone will figure something miraculous out that violates a basic tenet of my professional experience"?
Grandparent is trying to argue that a lot of smart people working quietly on something confers plausibility upon the premise of their work (i.e., "they must know something you don't"). I've rebutted with two examples showing that large numbers of smart people working on something don't make plausible a premise that is obviously flawed for other reasons [*].
[*] (ETA) and is known at the time by the smart people.
It might even be useful in other circumstances. Better radiative cooling systems, hardening commercial high-end compute for space, etc etc. R&D you can feel proud of, even if your bosses are only paying you to do it to fleece rubes who think it's the next trillion dollar industry.