I actually consider that the claim is not that bold, and in fact has been common in our industry for most of the short time it has been around. I included a few articles and studies with time breakdowns of developer activity that I think help to illustrate this.

If an activity (getting code into source files) used to take up <50% of the time of programmers, then removing that bottleneck cannot even double the throughput of the process. This is not taking into account non-programmer roles involved in software development. This is akin to Amdahl's law when we talk about the benefits of parallelism.

I made no argument with regard to threat to the profession, and I make none here.