"Vill de ha jobb än?" doesn't really sound natural. You'd need the "inte" that plays the role of the "inget" in Duo's sentence.
Vill de inte ha jobb än? = Don't they want jobs yet?
Vill de inte ha jobben? = Don't they want the jobs?
I'm not sure there would necessarily be a difference in the pronunciation of these two, but they would certainly come up in different situations: The first one has the focus on the "yet" (What? Don't they want (any) jobs yet? Why not now?), whereas the other one has the focus on the specific jobs that have been mentioned before and that these people don't want (with no mention about when).
Edit: Thinking even more about the pronunciation, the first one would maybe have the stress of the sentence on "än", because that's the interesting bit, whereas you'd not really ever pronounce jobben jobben, because that would be weird. Maybe in a different sentence where the issue would be whether you were talking about one job or many; jobbet vs. jobben.