But if FT was as promising as its advocates said it would be there should have been huge economic growth. We're not talking incrementalism here, we're talking about a massive experiment that has failed to deliver on its promises.
It has failed to deliver so far on its promise which are probably overrated. The EU is changing the way they do bookkeeping, but does not fundamentally change the countries involved and will not much be responsible for gain or loss. I think a single currency does make for more efficient trade and bookkeeping, but that is insignificant compared to the drag imposed by the welfare state.
You're confusing free trade with a common currency. The EU thought a common currency would expand trade. They were probably correct. Unfortunately for them, the massive regulation they added on everything from fruit content in jelly to food labeling to anything else to do with any product has more than destroyed any boost they might get from a single currency.
You thought NAFTA was a lot of paperwork, it's nothing compared to new EU regs.