Lack of trust, would be the obvious answer but when you come to think of it, bitcoin has already done quite well for itself over the years. It's steadily becoming a house hold name in just 10 years of existence. The like of bitcoin bonds, future contract trading and soon to be approved "ETF"are already mainstream material. Which means bitcoin is becoming mainstream as the day passing by.

Although bitcoin isn't yet where we thought it'll be by now, it success story has proven there's more room to achieve even more greater success, which achieving the mainstream attention is one of does. The approval of ETF could take the currency to another whole level of success. Let's give it (bitcoin) more time to continue proving its worth, maybe more 10 years.