Ask HN: Elizabeth Holmes has 200 patents – if tech didn't work, why not noticed?

I searched her name on a couple of patent search engines.

Turns out she has around 200 patents (with other people mostly).

So if her tech didn't work, then why didn't people figure it out sooner? Why did it take a journalist from WSJ to find the fraud?

How come some prominent physicist or biologist doing "competition research" didn't declare that the patents were based on bogus claims?