1k loc / week sounds like a lot. As a teenager, I got a tour of a company doing contract work for the government making drones. Their manager said they average 12 lines of "final" code per day per engineer over the course of a project. I was stunned and shocked it's so low, but it has stuck with me ever since. After many years more experience, factoring in bug rates and debugging time and meetings and rewrites and all the other things that eat time, I'm quite convinced that nobody goes as fast as they they think, and in reality all software dev is surprisingly slow, measured over the course of a large project. Granted government / military work is expected to run slower (and more carefully) than most software. But if you're writing code, you're creating bugs, and bugs take time to fix, there's no way around that.
12 lines/day/dev of "final" (tested, debugged, solves a customer problem) sounds about right.
The thing is - most code is not final. You end up writing exploratory code to test out a product, code that's rewritten because requirements change, code to test the actual code, code for projects that go nowhere and end up canceled, code for throwaway migration tools and other important tasks that aren't in the product but are necessary to build the product, code to make your job easier. All of that takes time, but it's not included in the metrics.
When I was at Google I used to joke that the half-life of my code was about a year, meaning that after a year, roughly half the code I'd written had been ripped out and replaced. Casual conversations with many other engineers indicated that their numbers were pretty similar. Over the course of 5.5 year career there, I wrote IIRC about 230,000 lines (there was a tool where you could instantly visualize your code delta across all projects you worked on). With a half life of a year, that's nearly 6 half-lives, meaning less than 1/64th of the code I wrote still exists in the codebase. It works out to about 3 lines of code/day, even though on an instantaneous week-to-week basis I was coding close to 1000 lines/week.
It can vary very widely. I recall somewhere in the work of Capers Jones there was a chart where they tracked lines of debugged code per staff month, and it varied from less than 100 to 5.000 depending on the industry. Which is to say that in some industries moving fast and breaking things is ok, and in some it's not.
