Nothing beats a prediction that you wont be around to take shit for when it is horribly off or to celebrate your oracular powers when when it is spot on. I appreciate your restraint and think you are probably right to do so, but why not at least a mention of the possibility of cryptocurrencies or some descendant of them playing a much larger role in 100 years? I suppose in a sense you could say your prediction is currency independent but the $ signs make it look like you only thinking about and in US dollars.