Probably not one currency, but the number of coins will be reduced drastically in the long run. Right now there is a "coin inflation", if you will, because a lot of people are trying to corner the crypto market by being the first movers. But once the dust settles, the number of coins will go down for sure.
It seems to be happening in waves: in 2014/15 there was a boom for new coins and literally hundreds of them were created, but they just went to be obsolete with few exceptions (doge, for that matter) when the wave has passed. Now there is a new wave but it will pass too. What remains after each new wave passes are those hundreds of coins worth a fraction of a dollar on coinmarketcap.com