If a metal based monetary system cannot prevent recurrent debasement of the unit of measurement either via direct physical debasement or via the addition of financial paper instruments then it has failed as a sound monetary system.
False premise. You claim debasement actually does anything. It doesn't. Debasement is just a lone actor thinking he can fool the market, but it's not possible. The market always routes right around it and adjusts accordingly. The market values by metal weight and content. The only reason Martin Scamstrong makes the false claims he does is because nobody had any equipment to test metals back then and had to rely solely on a maker's mark.
You no longer have to rely on a maker's mark at all. Metals were ironically not a trust free system in their mainstream hayday, but they are now. If anything, metals as a trust free money have actually improved, not worsened. You can even hold up a cell phone and do a ping test on a coin now and have your android app validate if the frequency was legit or not. Tools like that were not available to the common man back in the day, so he was essentially just using fiat. Thus everything abut Armstrong's premise is wrong.