That's a great point. It's not specific to software but knowledge work and creative work are nearly impossible to do without intrinsic motivation.
Because you literally cannot do things. Which things is completely and utterly irrelevant.
I don't understand why people still
a) think that "knowledge professions" are some kind of unicorn job where special snowflake sauce is required, and it's obviously totally different from those gritty "manual labour jobs" and you have to constantly set yourself apart (how arrogant is that?!)
b) purport this strange notion that psyche has little to do with the body. Digger won't dig? Just whip'em, it'll work for sure.