The crazy thing about Theranos is that so many people with experience in microfluidics (developed mainly for DNA sequencing although there are other uses) knew that their claims were impossible, technologically speaking.
Working with such small volumes to obtain quantitive estimates of blood chemistry is so implausible, as you are introducing uncontrollable variability - micro-evaporation, even tissue localization issues, I mean all the trained blood chemistry specialists knew this. I worked a little with DNA microfluidics, and it works because it's not quantitative.
Now, what they could have done is just stuck to pos/neg tests, i.e. 'are you infected with this virus or not' which is a lot more plausible as you don't have to meet a quantitative goal, just a detection goal. Also, one-stop STD screening for HIV / herpes / etc. is possible too (I suggested this and someone responded, 'new company name: ClapTrap").
It's really kind of sad, as Theranos might have been able to pull that off (although new management would probably be required), and then they'd have been positioned to do all the COVID testing (which was a major problem in the initial US response).
What just amazed me is how gullible all the investors were, and how they didn't do due diligence, hire outside experts, or anything. Weird.