Was it? I work in an adjacent space now (though didn't back then) and everything I've heard is that Powerwall 1 was vaporware. Even now, Powerwall 2s are hard to come by, though not to nearly the same extent — Tesla uses that product line as a way to soak up excess battery production when its car production bottlenecks, but historically batteries have usually been the long pole. That's essentially the only reason LG Chem/Sonnen/etc have any market share.