Probably because heads of state like to print it to solve their short term problems essentially robbing everyone with an inflation tax. I dont call that stable or just. I work and save and expect my currency to hold up and not be abused which is not happening currently.
Edit: HN must be the worst platform in existence to debate. I have about 700 karma and cant comment more than 3 times on this thread. Your rules are not helping discussion or clearing clutter, they're just really annoying. Retrac: no ive hit a limit and cant respond anymore on the whole thread even with only a few comments.