One of the key points in the article is that this is a partnership - while the EM has final say on the timeline, that's going to be influenced by the PM's produ

One of the key points in the article is that this is a partnership - while the EM has final say on the timeline, that's going to be influenced by the PM's product requirements. Maybe the PM says that the timeline quoted isn't going to work, in that case the EM is going to work with them to change the scope in order to better fit the timeline.