people around the world are not adopting bitcoin because of those thing in general
1- security
2- regulation
those two thing must be addressed in order to rise the adoption of bitcoin
the secuirty can be done by the exchage(so it's not even a bitcoin fault)
the regulation is on the way on some countries, but need to be speeded up and should be easy for average people, not something like "i need to take note of every transactions" or other things too laborious
Now, the question is who will take the burden to regulate Bitcoin. That will hell of a responsiblity because it's known that Bitcoin has security concern. There are illegal trades happening all over the world and the payment is happening in Bitcoins.