There are many cryptocurrencies out there, the fluctuation is wide and big. Theres a need of a coin that uses a process to stabilize its value.
No doubt that there is no other cryptocurrency or altcoin that can supersede the bitcoin. At least not for the next 5-10 years. Of course there are many rising competitors like Ethereum, ripple and litecoin.
Do you agree???
For now, i don't think any altcoins will replacing bitcoin even for years. The bitcoin value is the most expensive in the market.
With a small volume, bitcoin can the most market cap and dominance among all cryptocurrencies.
The most close altcoins with bitcoin i think it is Ripple, it has gone to 2nd position few days ago in coinmarket cap.