I don't disagree with you about leadership being hard. But the argument you use to get there is easily rebuttable:
> If leading people is so goddamn easy compared to software engineering, why do so few engineers want to move into people leadership,
a) because they wouldn't enjoy it as much as their current job?
b) because for engineers, being a manager does not give them status amongst their peer group.
> and why do so many of them absolutely suck at it?
a) citation needed. Is it provable that engineers are particularly worse at leadership than the rest of the population per capita?
b) if engineers tend to suck at being managers, it doesn't show that managerial roles are harder than engineering ones. How good are managers at attempting engineering roles, for comparison?