The million dollar (perhaps literally) question is – could @kentonv have written this library quicker by himself without any AI help?
But what if you only need 2 kentonv's instead of 20 at the end? Do you assume we'll find enough new tasks that will occupy the other 18? I think that's the question.
And the author is implementing a fairly technical project in this case. How about routine LoB app development?
This is likely where all this will end up. I have doubts that AI will replace all engineers, but I have no doubt in my mind that we'll certainly need a lot less engineers.
A not so dissimilar thing happened in the sysadmin world (my career) when everything transitioned from ClickOps to the cloud & Infrastructure as Code. Infrastructure that needed 10 sysadmins to manage now only needed 1 or 2 infrastructure folks.
The role still exists, but the quantity needed is drastically reduced. The work that I do now by myself would have needed an entire team before AWS/Ansible/Terraform, etc.
There was another article posted somewhere that made a parallel between the AI hype and no-code, outsourcing and other waves that have come.