Theranos was not a "complex business". It was deliberate fraud and deception, and investors that were just gullible. The investors should have demanded to see concrete results

I expected you to take this with a grain of salt but also to read between the lines: while some projects involve deliberate fraud, others may simply lack coherence and inadvertently follow the principles of the greater fool theory [1]. The use of ambiguous or indistinguishable language often blurs the distinction, making it harder to differentiate outright deception from an unsound business model.

[1] https://en.wikipedia.org/wiki/Greater_fool_theory