These guys are fooling themselves. Keeping the "Bitcoin" on their name only solidifies the fact that it's a knock off. They're never going to be able to win over miners, and they'll be far more vulnerable to network attacks as a result. Bitcoin Cash will be considered obsolete once the Lightning Network rolls out.
Bitcoin will eventually be replaced as the cryptocurrency of choice for regular transactions because of all its scalability issues, not to mention the high transaction fees. Really, the only thing that's stopping better designed cryptocurrencies from outright replacing Bitcoin is the lack of gateways into fiat. Coinbase already provides fiat gateways for Ethereum and Litecoin.
I don't see either one of those coins as being the ultimate replacement for Bitcoin, though. Ethereum has too many problems with its wallets and network, and Litecoin just isn't interesting to a lot of people. I think it will most likely be several other cryptos which replace Bitcoin. Bitcoin Cash is certainly a possibility
. I'd also consider NEM, DNotes, and DMD Diamond as strong contenders. Each one serves a different purpose, which is why I could easily see all three being used. They all have rock solid underlying technology (or are about to upgrade) and are easy to use (for crypto!). I suspect there will be a few others being used as well. STEEM is another possibility, though it has some network issues which could ultimately disqualify it.
Litecoin has faster transaction times, lower transaction fees, and has been growing at a better rate. Bitcoin Cash has always been doomed, as all it ever had going for it was the "Bitcoin" branding. I hold both Ethereum and Litecoin in higher regard.