Will the head coach (lets call him the Team CEO) get paid less than any coordinators?
NO - probalby just around million / year
Will he be powerless?
NO - Hire / Fire Coordinators / Oversees recruiting / Has Game day responibilities
Answers to Whit
The difference is, the head coach is NOT responsible for the Offense / Defense / or Special Teams Performances.
That is the job of the Offensive / Defensive Coordinators and Special Teams Coach

So the Pressure and responsbility of the performance of the team falls on the coaching staff and coordinators. And they must get the job done.

If you take these responsibilities away from the head coach, alot of the pressure is gone.
Hence the lower pay. This allows more dollars to go to the staff, to put the product on the field.