People do not understand the power of blockchain technology and simply choose to ignore it. Those who are interested are often turned away at the complexity of investing in cryptocurrencies. Lots of the exchanges are unheard of, and therefore not trusted, especially seen as many have been hacked before.
I believe one the barriers of entry and general knowledge of blockchain technology increases, then we will see the mass public rushing in. This is likely going to be in 2018, especially seen as global regulators such as the Financial Conduct Authority (FCA) are looking into regulation of this market. Regulation of the market creates a level of trust between cryptocurrencies that is very much needed for public adoption.