Coinbase said they would add BCH withdrawals to their exchange (for funds that were on there during the split) sometime before the new year months ago, and then

Coinbase said they would add BCH withdrawals to their exchange (for funds that were on there during the split) sometime before the new year months ago, and then consider whether to add trading at some unspecified point in the future after that. There is a very big difference between the effects of dumping a bunch of formerly-illiquid funds on the market and opening up a new market to buy something.