AI isn't mature enough to replace all creatives. If they push back now while they still have leverage, they can block AI from getting to the point where it can fully replace them.
Once it's an industry and cultural norm, there's no going back. They try now or it's over forever.
Assuming that creatives can be replaced by AI (meaning there isn't some soft cap on how good it can get for technical reasons) then creatives will be replaced with AI. The only difference striking makes is whether it happens in 5-10 years or 10-20.