IF btc becomes a reserve currency with the same status as.fiat currently does, it will take a LONG time. Revolutions don't happen.overnight.
Bitcoin isn't going to become a reserve currency. Bitcoin will always be tied to fiat because it's pegged to it. It would need to break free of it but the only way I can see that happening is if major currencies collapse themselves and bitcoin becomes a dominant currency in its own right which I don't think will happen.