Understanding what makes Bi$_2$Sr$_2$Ca$_1$Cu$_2$O$_x$ (Bi-2212) the only high critical current density ($J_c$), temperature superconductor (HTS) capable of being made as a round wire (RW) is important intellectually because $J_c$ RW Bi-2212 breaks paradigm that forces biaxially textured REBCO and uniaxially (Bi,Pb)$_2$Sr$_2$Ca$_2$Cu$_3$O$_x$ (Bi-2223) into tape geometries reproduce strong anis...