Before Monero started its big run I said it would be a billion dollar coin. There will be others as well. And some trillion dollar coins.
Trillion? That must be a sarcastic passage, isn't it? Since bitcoin on its tops only reached $10 billion, I think no one can ever surpass that unless big corporations conspire to create a huge bubble out of an altcoin--which is highly improbable, to say the least. We might see multi-million blockchains to grow as long as there are developments being made like LISK and ETH.