Is there even a concrete proof to show that this is really happening at all, they are just speculations and I haven't heard about anyone talking about an attack on the bitcoin network as at now but whatever they are doing, it's not going to succeed.
I do not think that such thing is going to happen, bitcoin has its strength, and i think that bitcoin remain as more powerful, because bitcoin popularity is increasing from time to time which is giving more support to bitcoin. I think bitcoin cash will also survive for a long time but still it cannot replace bitcoin.