This is really spot on. The only thing I could add, is that I've found the only way to continue to write code in the capacity he's talking about, is to dedicate a day or days of the week to programming. If you're going to make your 1,000 or so lines meaningful, then the context switch to that mental state is too high when your day is intermixed with distractions.
Sometimes I can put my headphones on at the end of the day and try to get 2 hours in; or work the graveyard shift at home but that's never as good (or healthy really).
I tip my hat to the pure engineering managers who don't code at all. They're more like social engineers than anything, but boy would that be challenging to do 100% of the time.
The best managers I've had were ex-engineers who realized that they couldn't write code any more. One of them explained it like this: "You get your work done by moving lines of code around. I get mine done by moving people to where they're needed, a little like chess." And it was true: He was tuned into the technical issues, and knew what his talent pool was, and was quite good at helping people make decisions about what to work on.
The worst managers I've had have been the ones who thought they could do engineering plus "the people stuff", whereupon they stunk at both. (Well, not the worst -- the absolute worst tried to make all the decisions, too: Code it this way, little robot. Or neck-and-neck, the managers who made no decisions at all and left everyone rudderless until they decided on a product and a deadline; ugh).
Back to coding, that's roughly 50K lines of shipped code a year, which seems pretty high to me. Well, you can definitely do that in a green fields area, like a totally new feature or product. But writing that much code in an existing system is gonna be hard.
Sometimes I can put my headphones on at the end of the day and try to get 2 hours in; or work the graveyard shift at home but that's never as good (or healthy really).
I tip my hat to the pure engineering managers who don't code at all. They're more like social engineers than anything, but boy would that be challenging to do 100% of the time.