As the btc is spreading and growing all over the world day by day altcoins also will grow. As we all know that people are like crypto currency so much and then altcoins will also grow and the future of altcoins are bright.
Monero is a excellent coin and it proved itself . people also like monero so much but become next BTC i think is very very difficult because BTC is the king of coins and it is available everywhere in the world.People trust BTC more than any other coin.