Cryptocurrency is future. Not only BTC. In future we will see more new cryptocurrency.
i do not think that other crypto currency will be future of money and i think just bitcoin will be future because bitcoin is very much stronger and popular crypto currency and bitcoin is very useful currency and it acceptable and available in everywhere for online transaction.
Thinking this way is foolish and naive. Yes, Bitcoin is currently more popular and as you say stronger in terms of value per unit, but there are some serious altcoin contenders up and coming. The whole cryptocurrency "scene" is still in its infancy and basing such predictions on just a few years history is foolish. I believe bitcoin will maintain a strong presence, at least for the next few years, but who knows what will happen in the next 5, 10 or even 20 years.