There's a difference between doing something hard and running a scam.

Theranos defrauded investors, healthcare services and patients. The product did not work but they pretended that it did.

Regardless of what theranos was actually trying to do, saying: you should try to do something hard first because it then becomes easier to do subsequent things, doesn't mean guaranteed success at achieving hard goals.

They overpromised and doubled down on scams. The core idea was good, read somewhere that some ex-Theranos people are working on more realistic/humble implementations of that same idea.