As you allude to, that's an argument based on the basic biology and statistics, not based on Theranos. You could have made that argument pre-Theranos. That Theranos tried, failed, and the covered it up is not much new evidence. Lots of companies try and fail on hard problems all the time.

Given that the above test is some random marketing PDF and I haven't heard anyone respectable talk about this mechanism, I don't have much faith in it, so that is consistent with your analysis.