The key issue right now is that the models falter in the last mile, and the last mile is where you need the training and experience to make sure the thing that lands is production quality.
At some point in the next few years I believe the roles will merge. I suspect that PMs will be forced to specialize towards a discipline (design, data science, engineering, etc.) while engineers will also start to see more of their responsibilities covering former PM territory. Most engineers will probably become closer to “product engineers”.