Well first of all bitcoin becoming a currency is not possible at all because the price can't be controlled by any government as currency can have a bit difference but with bitcoin it isn't possible.
Second bitcoin is a investment platform and if it would be a currency then calling it an investment platform or in other words next gold won't be possible.
Third even if somehow it became a currency there wouldn't be sufficient stock as total number bitcoins allowed to be mined is 21 million and 14 million bitcoins are already mined so there would be a shortage in distribution of it.