This theory seems to debunk the classical "people need an economic incentive to do their jobs"

This suggests that if you pay someone to do X, they will be less likely to do X as a hobby, and enjoy X less while they're doing it. That does not imply that if you didn't pay them to do X, they would do it enough to satisfy the job requirements.

There are cases where that's true- open source programming comes to mind- but they seem to be the exception, rather than the norm.