In my opinion they want to be safe with their money, and think that gold is safer. They are not interested in technological development because they think it looks virtual and complex.
I think that the main reason is that bitcoin is still very new for them and still they do not have enough knowledge about it. I hope as soon as they will get knowledge about bitcoin and other crypto currencies they will surely start taking interest there, because in current time crypto currencies are more profitable than gold and silver.