I can't find a link, but I've seen multiple reports that VCs who actually worked in the medical field passed on Theranos because it looked and smelled fishy. The people who kicked in big bucks, like Rupert Murdoch, swallowed the hype and the celebrity endorsements.
Yes, noticeably little investment came from biotech which should have been all over this. It did not make sense. it was the range of different things offered, not the number of tests. We will probably be able to screen for hundreds of illnesses on a few drops of blood looking for DNA. Genomic DNA for genetic predisposition, cell free DNA for early cancer diagnosis. Bacterial and viral DNA / RNA for infections. At some point we will need AI to process the volume of data, but this is all essentially the same technology and a simple advance on what is currently done. It makes sense. what she was offering made no sense. i can remember reading about her, and the company and trying to work out how she could possibly do what she claimed, and I couldn't. so I thought it was fishy. The biggest give away was no patents. Any real innovation would be surrounded by dozens of patents.