As far as I know, BNB is an ERC20 token based on the Ethereum blockchain, so BinanceCoin is highly unlikely to beat ETH. Ethereum is a platform for hundreds of different tokens and many people use this ecosystem every day.

A few months ago, BNB developers launched Binance DEX but in my opinion this decentralized exchange still does not look attractive to large investors. Some teams are now running their IEOs on the Binance and other crypto-currency exchanges so undoubtedly this is an advantage for the BNB price. Frankly, I do not believe that the BNB capitalization will surpass the ETH capitalization.