Marketing is likely one of the most vulnerable areas, but even there marketing needs are likely to expand to smaller businesses with less emphasis on it now. My old engineering company likely can loose 10% of staff as a few people that we have to handle overflow could be phased out. On the engineering side itself history has shown that the "easy" bottom 10% gets some automation, but there is no good way to address the balance, which actually ends up expanding. An example could be modeling multiple scenarios further into a project in order to maintain value engineering options or design for prefabrication.
Copy writing positions and responsibilities will shrink, but the time always ends up being taken by something else. Any really big changes are further out than a 5-year horizon.