Interesting thought for sure.
Here is a way that it would maybe work?
HD takes the two lowest populated worlds, World Y and World Z. World Z has the less coaches than Y, so Z is designated as the world being "killed".
Now all the coaches from world Z are presented with the one time option to merge there coach from Z to Y. If they chose to do so, so they will be allowed to apply for open jobs based on their world Z resume.
If a coach had a team in both worlds, they would be presented with the one time option to use coach Z's resume for that seasons job application process.
This would increase world population, however HD would still lose money since there will be coaches who do not merge.