That’s the hard truth:

Even deep expertise in widely-used technologies won’t protect you if your work doesn’t drive clear, measurable business outcomes.

The tools may be critical to the ecosystem, but the companies decided that further optimizations or refinements didn’t materially affect their goals. In other words, "good enough" was good enough. This is a shift in how I think about technical depth. I used to believe that mastering internals made you indispensable. Now I see that: You’re not measured on what you understand. You’re measured on what you produce—and whether it moves the needle.

The takeaway? Build enough expertise to be productive. Go deeper only when it’s necessary for the problem at hand. Focus on outcomes over architecture, and impact over elegance. CPython is essential. But understanding CPython internals isn’t essential unless it solves a problem that matters right now.