BTC is now the base.
Most of the exchanges have BTC as prime currency to trade with.
If BTC will have the hard fork, means BTC will sink.
Is that means that all exchanges will now put ETH as prime coin to trade with?
There is now way for ethereum to replace bitcoin. Thery are very different coins. Consider bitcoin as the fiat money of crypto market and ethereum as just a functional asset.
Let's go back and compare ethereum with waves, bancor and tezos. Bitcoin is not comparable with others.