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
There is a big gap if we will look at the difference between the the principle of trading between gold and bitcoin. At the point the bitcon in terms of transactions could offer a faster and more ways to deal with. While gold as you say it is tangible meaning that it needs physical wulatiy or equivalent value for it to have a trading value in the market.
but the value of gold always rises with time running. and of course everyone wants to have gold. but, for now, people tend to want to have bitcoin, because it's significantly faster than gold.