The “network effect” of bitcoin will bitcoin to retain dominance or supercede nearly all other altcoins. Look up “network effect”.
However, I’m looking forward to zcash, at z.cash URL, which will have really strong anonymity features, much stronger than bitcoin. It is supposed to come out later this year.
Bitcoin is not really anonymous, as you can be tracked down by various means. Not with zcash. zcash is being made by reseachers at MIT, Johns Hopkins, and the Technion in Israel.
Plenty of other cryptocurrencies out there...BTC is the biggest market cap by far tho.:
https://coinmarketcap.com