You probably accidentally did an ACH transfer instead of a wire transfer. Coinbase does not support ACH.
There's plenty of people online complaining that wires in and out of Coinbase from December 12-18th have yet to process. There's even a class action lawsuit being formed about it.
My worst fear is that Coinbase is insolvent.
Surely they would have to be thoroughly pwned for that to be true? They claim that 98% of customer funds are in cold storage, and they ought to be raking it in on transaction fees and with BTC being up 1372% this year. They also raised a $100M Series D round in August. It's not impossible, but highly unlikely.