I think bitcoin cash will be very difficult to be able to replace bitcoin, indeed bitcoin cash has a high value in the market, but ethereum still has a higher position, if bitcoin cash cannot match the ethereum position then it is very unlikely for cash bitcoin to replace bitcoin
bitcoin will still be the number one coin, with a limited total supply making bitcoin will have high value in the future
Bitcoin Cash will only replace Bitcoin if some day Roger Ver identified as Satoshi Nakamoto, the founder of Bitcoin more than ten years ago.
Unfortunately, the probability that Roger Ver is truly Satoshi Nakamoto is low as 1/million.
In a conclusion, Bitcoin Cash will hardly replace Bitcoin, years from now.