Only people buying gold are those who aren't modern or smart enough to buy bitcoin. Someone tell them to sign up at coinbase, it's a simple exchange and even n00bs can buy a bitcoin or two
Most people still referring to gold as the best investment and most of them don't know about bitcoin. But people who already know gold and bitcoin, he will buy both gold and bitcoin, and I am sure that he doesn't have any problem to buy both at the same time.
Besides that, gold will be rare, and the price will increase higher, and this makes people want to buy gold as much as they can. But on the other side, people have another option which is they can purchase bitcoin too for the next generation of the investment.
With the growth of the technology, people will learn, and they will found that there is a new investment type that will be available in online and offline and they can use it too for paying something for their daily life in the future.