The first question anyone should ask when something like this happens is "What caused it?"
As you now know, in this case it was Coinbase transferring BTC holdings into BCH for those that had requested it prior to the fork on August 1st. This means that despite what many will believe, it was NOT a major sell-off. Of course, now that Coinbase is offering BCH there may be many more buying into it, especially having seen growth of over 50% in under 24 hours, but these people will be doing so because:
a) they didn't know what caused that sudden hike, and
b) they buy what they consider to be most popular, and never take advantage of the dips.
I don't know if BTC will recover and hit the $20k mark this year but it is very likely to do that in January. BTC still retains the largest market cap (over 5x greater than BCH) and will undoubtedly rise to incredible heights in 2018.
Roger Ver may claim his product is superior, and that may well be true, BUT he has not understood that you do not have to have the best product in order to win the largest market share. Just look at the auto and technology industries if you don't believe me.
Why would coinbase transfer BTC to BCH for holders that requested that? They and everyone else who has priv key got an equivelent of coins on the BCH blockchain since it split, they do not need to do this.