Aside from whether their technology actually works or not, the central premise that cheaper, easier and more frequent testing will improve outcomes is unproven. There are many potential downsides. It might increase health spending through extra doctor visits, the need for repeat testing and more invasive and expensive investigations. But will it actually make anyone's life better? Bear in mind that even a single, obvious test performed in a high risk population to screen for say breast cancer or ovarian cancer, either barely moves the needle in saving lives or ends up being useless. What effect does Theranos think indiscriminate widespread testing will have?
With all these competing risks, this frequent testing strategy needs to be evaluated in randomised double blind clinical trials. Before that though, Theranos needs to submit their tests for independent validation in many thousands of patients, and publish the results.
I note this single study which compared Theranos' CRP to a conventional method [1]. The Pearson correlation was 0.85, which I don't think is really good enough.