Op is asking a lot of questions, and such questions require diving deeper into the world of economics, but some statements are also opinions. For example, fiat is not doomed to fail, it's been operating quite successfully globally. Also, the gold standard was abolished for a reason, and it's debatable whether it was better than fiat. Bitcoin is also not something we can confidently claim to be better than fiat and the gold standard. It's just different, as it is not issued by a central authority, its supply is coded to work in a certain way and involved mining (which is where comparison with gold comes in).