Everything you say is true, and leads to the oft-repeated "why would I want to learn this complicated programming concept, when my job doesn't require it?". Tha

Everything you say is true, and leads to the oft-repeated "why would I want to learn this complicated programming concept, when my job doesn't require it?". That is, it encourages the idea that employment is the yardstick. The rub is that this all depends on what you find personally rewarding. If what leads to a rewarding life to you is having a good job, then absolutely, you probably don't need more than a certain amount of depth and knowledge on the subject. But if depth and knowledge on the subject is what you find personally rewarding, then suddenly putting in all this work makes sense. For many, lifelong learning is what is most rewarding and brings most joy, which one might argue is the most important thing as long as you have a sufficient income. If you do want to frame it in terms of achievement, it's also obvious that many prolific people in their fields were driven by a passion for what they do — the playful nature of Feynman, Shannon and others comes to mind.