It will probably remain dominant as it has the pioneers advantage; I say dominant, but it could only be ahead of all other cryptocurrencies by just a few percentage in terms of market cap.
Bitcoin is remain dominant the sense as it is the first ever made crypto currency and will always be in the top most position in the crypto market as it is the parent of all crypto currencies and all other alternative currencies are just following the first crypto currency. The demand for bitcoins keeps on increasing every day even though there are lots of alternative in the crypto market.