The above are the tests in common use world wide in clinical labs. If you know of a company contemplating making a machine which can perform a worthwhile subset of these on a drop of blood, I'd love to see the reference and the link. And I would certainly invest if credible testing had been done and appropriately reported. But then again, so would every venture capitalist be willing. Yet, this is what Theranos was implying they could deliver.
They are many labs worldwide accredited for the panels that Theranos was proposing in capillary blood. Again, Theranos failed not because they were proposing more than they could analyze in one drop of blood but because of the lack of compliance with current regulations on laboratory testing. See what John Carreyrou said on it: "This fiasco could have been avoided had Theranos sought accreditation from the College of American Pathologist (CAP) by submitting actual tests run on their equipment for appropriate testing. Based on the recent revelations, the results would not have been accurate and they would not have received CAP accreditation. Only labs that have CAP accreditation should be in the business of performing blood laboratory testing. CAP standards are exceedingly stringent and exceed CLIA certification. The FDA acted appropriately and responsibly in this case."
Again, some labs do propose under their CAP accreditation the same panels that Theranos was proposing. These tests are as precise and accurate as tests done in venous blood. The issue is not that the technology does not exist but that Theranos didn't bother to comply with current regulations.
Now, with regard to the number of tests that today's technology can allow in one drop of blood, sure if one use immunoassays that require a given amount of blood per biomarker, one cannot extend the panel to more than 20-30 analytes. However multiplexed assays such as LCMS do not have this drawback and some CAP accredited labs do already propose the measurement of thousands of molecules by high resolution LCMS in only ten microliters of blood.