You have general contractors and then you have subs that work under them. A general contractor is a jack of all trades, master of none. Exactly what a full stack developer is.
This isn't the end of specialization. It's the beginning of project management steered by developers who intimately understand all of the work involved, even if they aren't as competent as the specialists.
Having a team consist of all full-stack developers is just stupid. Having a full-stack developer as the head on a project, with specialists on the team, is a great idea.
A software lead is one a type generalist, as they have to manage resources that can X, Y and Z. The generalist position described in this article is someone who can and will dive in and do X, Y and Z themselves. Very different roles.
It's the beginning of project management steered by developers who intimately understand all of the work involved, even if they aren't as competent as the specialists.
People with a wide breadth of general development knowledge, once employed as developers but now managing development? I wouldn't exactly call that a new idea. Or are you talking management that also develops across all components of the software? If management takes up so little time of a single developer's time, then you're just using different words to describe the small team constraints that the article does.
In practice, though, it seems like the minimum bar for entry becomes "full-stack experience" and then understaffing, because why bother hiring when these people can do everything anyways?
That's how the HR and operations folks screw it up.