These people never stops about the fact that bitcoin cash is just another alt coin in the market. Bitcoin is bitcoin and it will never be replaced by another alt coin, it can be upgraded into v2.0 or something similar but it will remain bitcoin. Put that in your mind that everyone will still stay on the original bitcoin. And that's not BCH.
But you're forgetting that Core just forced thru the Segwit changes to "original Bitcoin". So "original Bitcoin" is not really Bitcoin anymore either. Rumor has it "original Bitcoin" may forking again when they refuse the 2MB hard fork of Segwit2x, because Core wants to start banning Segwit2x nodes...
At some point "original Bitcoin" could be so crippled that it loses value, That's where Bitcoin Cash could step in.
Bitcoin will always remain bitcoin. Because of Segwit it will not be called as the original bitcoin anymore? If you say so, if you want to push bitcoin cash for another highlight or you can see that this is going to be a good choice for everybody when it comes to transaction. Do it for yourself, well it's a fact that bitcoin's value can lose suddenly but if you think that BCH is the successor, I don't think so.