To answer your question, yes it can be profitable. But it does not have much to do with difficulty to be honest. Think of difficulty as an consequence of the hashrate. e.g. hashrate goes up difficulty goes up, hashrate goes down diffuculty goes down.
But don't expect to be mining BCH anytime soon and make money with your GPU's
Thanks. Guess it just depends on if it dies completely. Nobody mining it, nobody is interested in it and it becomes worthless.