The bottleneck in programmer productivity is not the number of lines that he writes.

It's the number of understandable lines.

(lines of his code and all the libraries beneath it).

When I write 5k lines of code, I flash out the bugs and everything works fast and robust.

But when I write 1k lines of code, but also use a library that I don't understand fully(a.k.a. I didn't write it), then I keep getting bugs all the time.

I observed this when I rewrote a spreadsheet from ReactTable to vanilla JS. I don’t have any problems with vanilla JS. But I had a lot of problems with ReactTable. I needed to debug it, understand how it’s made, because the docs(even though they are good), don’t explain the full architecture of the thing.

So the bottleneck is not the code.

It's understanding of this code.