I am not a lawyer, this is just my rationale:
Holmes clearly lied to investors, and even if she may have "believed" in the long term prospects of her company, she also clearly intentionally lied to investors to get their money. The investors were also obviously harmed (they lost their money). Also, the fact that VCs expect a lot of their companies to fail is totally irrelevant. VCs (and more importantly, the law) also expect founders to tell the truth on simple statements of fact, e.g. "We recieved this much revenue" or "This machine can perform X, Y, Z tests now". Again, Holmes didn't just exaggerate or say "This machine can perform X, Y, Z tests in the future". She flat out lied about the current capabilities of her company.
With patients, most of the tests were done on standard equipment. I don't believe patients were ever told "we will test your blood on Edison", and more importantly, they probably wouldn't have cared that much - they just wanted their test results. So with the tests done on standard equipment, hard to argue there was much harm done there.
Now, some tests were done on Edison, and I know Walgreens invalidated a whole bunch of Theranos tests. But even then, it's harder to say Holmes intended to deceive in that case (a prerequisite for the fraud charge) - presumably they chose to run them on Edison and not the other equipment because they thought Edison could handle those tests. The fact that the lab was sloppy, the fact that Edison had issues, that in my mind wouldn't be enough to assert wire fraud on the part of Holmes. All in all it's just kind of hard to say that patients were really defrauded at all. If Theranos had instead just completely made up some of their test results, and Holmes directed that behavior, then yes, that would have been fraud against patients, but that's not what happened.