I think the Harmonic Generators were cool amps. PRS was a very small company back then and they came into being at a time when music was changing. A lot. Vintage tone and hand-wired quality weren't mainstream. Grunge was a flash in the pan. Then things changed again. "Failure" might not be the right word.
Is this thread about bad ideas or production numbers? If the later, Chesapeake instruments wins the prize. Only 19 "production" guitars were made bearing the Chesapeake brand name (as built by Private Stock) before it was shut down. Again... "failure" might not be the right word.