"It seems pretty intuitive, so maybe it's already largely applied?" It is! That's why doctors don't order every single possible test every time you show up sic

"It seems pretty intuitive, so maybe it's already largely applied?" It is! That's why doctors don't order every single possible test every time you show up sick! That's also why consumers SHOULD NOT be testing by themselves without medical supervision (I'm looking at you, Elisabeth Holmes and Theranos).