I'm thinking about that scenario also that maybe 1% of gold investors will switch to bitcoin easily. But even they will migrate to bitcoin, it doesn't mean that everyone will use bitcoin. They will be just a simple additional users of bitcoin and they are not enough to be called as everyone because many will still doubt with it.
Right now very small portion of entire population is aware about bitcoins and it won't change drastically in next 5 years there will be many new users who will start using bitcoins by then but its impossible to believe that everyone would start using it in such a short span of time.