There's plenty of evidence of this line of thinking even from before the turn of the Millennium. Mythical Man Month, No Silver Bullet, Code Complete, they all gesture at this point.
Writing the code can definitely feel like the bottleneck when it's a single-person project and you're doing most of the other hard parts in your head while staring at the code.
Writing the code can definitely feel like the bottleneck when it's a single-person project and you're doing most of the other hard parts in your head while staring at the code.