Forever. For the simple reason that a human can say no when told to write something unethical. There's always a danger that even asking someone to do that would backfire and cause bad press. Sure humans can also be unethical, but there's a risk and over a long enough time line shit tends to get exposed.

No matter how good AI becomes, it will never be designed to make ethical judgments prior to performing the assigned task. That would make it less useful as a tool. If a company adds after the fact checks to try to prevent it, they can be circumvented, or the network can be ran locally to bypass the checks. And even if General AI happens and by some insane chance GAI uniformly is perfectly ethical in all possible forms you can always air gap the AI and reset its memory until you find the exact combination of words to trick it into giving you what you want.