I think we will see crypto move towards the mainstream in the next few years. There are a few key obstacles that need to be overcome first. One is legislation, and that elusive SEC approval. Another - more for smart contracts than BTC - is the spread of IoT and 'smart cities', for which the 5G network will surely provde the backing infrastructure. We also need the markets to start to mature and become less volatile, which will probably come naturally with increasing volumes as crypto become more popular. I think we might also need some crypto project to be embraced as the most efficient and most profitable solution, to kickstart the era of crypto dominance over fiat - chances are this will probably be XRP for international corporate banking.
But yes, I think mainstream is inevitable.