I sympathise with your general point although as an aside I'm not sure this is accurate: > Feynman loved physics long before physics became world-changing. Fe

I sympathise with your general point although as an aside I'm not sure this is accurate: > Feynman loved physics long before physics became world-changing. Feynman was an intensely practical person and learnt a lot about physics from e.g. fixing his neighbours' radios as a child. And radio is certainly something I'd class as "world-changing". He loved physics because of the things you could build and create, and did not enjoy abstraction or generality for its own sake. A better example for your argument might be Hardy, who explicitly stated that his love of number theory was partly due to its abstraction and uselessness. This was long before it had critical applications in cryptography.