Of course, manufacturing capability is important for a nation from a strategic viewpoint. But even if the manufacturing returns to the country - the fact of the matter, is that those manufacturing jobs are never coming back. It will all be done by robots. This process is already well underway(https://www.ft.com/content/7eaffc5a-289c-11e6-8b18-91555f2f4...)
So those politicians speaking to old people in steel towns are misleading them and giving them false hope. Bringing manufacturing back isn't going to do much to reduce unemployment . That seems to be the point of the article.