Bitcoin is just 6 years old. It is still in early stages. It will take a few more years for it to be more widely used.
Exactly my opinion. I think it will take quite some time to break into the mainstream unfortunately as sadly most people don't really have any real use for btc over their fiat and see it as a risky venture. I think it will gain traction in certain industries like gambling and remittances first and hopefully it becomes the first worldwide currency at some point. That would be awesome.
It is not into mainstream because still many people are not aware about what bitcoins is all about, how it is helpful, how it can be used and what are the future benefits and that is the reason people hesitate in investing in bitcoins and the price volatility is the other factor and that is the reason people find it too risky to invest as they have fear to loose their money.