As by seeing the usage graph and profiting graph i can easily assume that in next decade of 2020 people will mainly relay on bitcoin and the main thing to survive in the next era will be bitcoin and it will be frequently used by everyone and that will help many regions to boost their economy as well so hope for the best, many people are eagerly waiting for the btc system to be implemented.
You have a point that it will happen but still, there are people who will depend on cash because it is where tgey really inclined in. I hope if it will happen it will not be hard to the people because it is a big adjustments to everyone.