this was one of the most impossible scenarios I have heard and it did not occur in the end. I dont say Bitcoin Cash is worthless but even the current price and market cap is way too high
My random guess is that thing will just like how ETH and ETC compete, at the end, the original ones always win and hold their value or even make the value goes to the moon.
There's no way that BCH could have equivalent value to BTC while the marketcap, demands, and many factors isn't the same. There'll always gap betweet each other's value, depends on how the community think what they deserve.
and my speculation is that, when BTC will always have significant higher value than BCH.