Have to agree with the article somewhat. Its very difficult to be great at every part of the stack. Big companies require this as their applications last longer than the usual startups. Backend developers think they are full stack if they can throw HTML and JavaScript on the page. The current state of things is that the front end of things is way more complex and having to consider user interactions ends up being as hard as throwing crud together.
On the other side of things, I know Frontend developers who wouldn't dare touch the backend for any reason. So A full stack developer for most companies someone who is willing to do back and front end development if they have to in order to ship a product.
For myself, if I don't like the backend stack I'll stick to the Frontend of things as that is what I specialize in. If the backend stack looks interesting to me then I'll want to work in it. Fortunately, I got a job at a company who can offer me a stack Im interested in on both the front and back ends.