I also don't think that this slump that we are seeing is caused by Bitcoin Cash, they have done their share of attacking bitcoin, but they are not successful. So for now, step aside Bitcoin Cash they have nothing to do with it. As for altcoins like XRP, I could only speculate that bitcoin investors are moving and shifting funds across to XRP, it has been pump at more than 50%, so it could be another contributing factor. Another is that is just the holidays, people cashing out spending their profits in this season, Its already Dec. 31 here at the other side of the planet, I have cash out myself so I attribute everything in the holidays. 2017 is almost over, and once everything has settled down, maybe we can see in the second week of January that trading will pick up once, and we may see bitcoin going up again. No need to worry and panic at this time.
Yeah, wouldn't make sense to suddenly see Bitcoin Cash's ongoing campaign show its effects now when they've actually done their worst already. Even the spam attacks on mempool aren't as bad as they were a week or more ago, although holding around 175k for many days now is a real show of financial strength (anyone realise the fees in mempool are growing bigger too?).
This is just the slump that Bitcoin's in. The correction took its toll on nerves, the recovery was never going to be long-lived, and this struggle is going to be a long and arduous one. Everyone's literally waiting for New Year to arrive, and then we'll see a renewal. Up or down? Not worth guessing at, but what's for sure the volatility and swings will pick up again. January is historically a down time, though. We'll see if that trend holds.