To some degree, both categories can also co-exist in the same person.
Some people are self-motivated when crunching numbers on spreadsheets because they find it satisfying but would need to be dragged kicking and screaming to provide phone support -- and vice-versa.
And there are probably some jobs that it's more common to be self-motivated for than others. Garbage collection? Data entry?
I'd say both exist in every person. I'm a software engineer with some design background. I got into programming because after trying to get into design, I found it wasn't my thing, but I've had many employers that wanted me to fill in the gaps the design team left open which I hated doing. It comes down to learning what motivates each employee individually. Companies spend so much money on surveillance and productivity monitoring, but don't spend much if anything on taking inventory of employee skills and strengths.
Even development. I hate having to deal with project management software, detailed estimations, estimating points, etc. I know some of the drudgery of process is necessary, I just don't like it.
Some people are self-motivated when crunching numbers on spreadsheets because they find it satisfying but would need to be dragged kicking and screaming to provide phone support -- and vice-versa.
And there are probably some jobs that it's more common to be self-motivated for than others. Garbage collection? Data entry?