Not sure what your thought are on "few" currencies that survive, but my opinion is there will be a large number of currencies that survive. While I believe the joke currencies will die away, there will be a number of currencies that serve a purpose. That is part of the beauty of building a currency on a blockchain. You can tailor it to fit specific sets or applications. I highly doubt there will be a one or handful of currencies that "fit" all.

You are not looking at the next one big thing, but you are looking at emergence of an entirely new market that is here to stay and slowly replace fiat. I wrote another post on where I think the market is going that is very relevant to this, I'll drop it below:

"Bitcoin and cryptocurrency in general are still in their infancy. The market cap is at 173 billion. This is a technological innovation that I believe will change currency and take over fiat for good. It comes at a very interesting time, where companies are racing to bring the internet to the half of the world that does not have it. As this happens, it opens the entire worlds currency to the potential to move to digital.

That opens the question of what is the currencies potential. Well in my opinion, it would be that of the world market cap, which would put it at 70 trillion dollars. That means that we are currently still in the innovator phase of the technology adaptation. This is the term assigned to technologies below a 2.58% adoption rate.

As we move forward along the technology adoption curve, we will pass through several additional phases, the early adopters phase, the early majority phase and the late majority phase. During these phases, the rate of growth increases drastically as we move into the early adoption phase and then goes almost exponentially into the early majority phase, and then tails off a little as we progress into the middle of the late majority phase. What this means is that the biggest growth for the cryptocurrency market is still well ahead of us. We should see the prices of cryptocurrency continue upward for a long long time as the market cap continues to increase and the growth rate continues to increase."