As far as I know, we are slowly going mainstream which will take time but what I know is people are scared of trying something new like the blockchain technology or people are still living under a rock with no knowledge of whats to come or maybe they do not know the benefits of the technology.
Rulers want to keep control and power over their established system. One difficulty I see is to not have a privatised framework, as we have it now.
The blockchain must remain free!
This is one valid reason, people do not want to lose control when bitcoin or other cryptocurrencies are adopted as they will disrupt this monopolized framework