Well in my opinion, bitcoin will never be equal to gold because gold has physical value and represents for the whole economy while bitcoin is just numbers. One possibility for that to happen is we lose all our gold
Think at services, it isn't' a touchable thing but still you gain some comfort of it, you can't touch the work of a person. The same goes with bitcoin but in a more complex mather. Gold gained field during wars, even if national currency was under inflation gold stayed on his foot because, people believed that is more safe to have holding in gold then in other currency. Gold is a shiny metal, probably as rare as bitcoin.