This one gets beat to death regularly. You simply cannot compare salaries flat across the country and there is no "average" that has any meaning.Factors that enter in are:
The general cost of living - San Fransisco and Key West come to mind as areas where managers have to make more just to keep from living in a flop house.
The progression of wages up the corporate ladder. The CFO and upper management don't want managers making more than them, even if the manager works harder.
Skill and experience. A very few managers are recognized throughout the industry as star performers. These guys and gals can prove that their higher wages will increase business. Sadly, the burnout rate is high.
Alternate compensation. I've worked for theatres where lodging was part of the package, and percentage of concession sales is a common perq. Some companies have yearly or quarterly bonuses and incentive programs, sometimes based on group ticket sales or other promotional programs. All this has to be factored in.
Load on the theatre. With rare exceptions, the budget for a theatre is set based on past performance and projections. Some theatres simply can't support a decent manager wage, no matter how great the manager.
The only meaningful comparison you can make is to find the competition wages within the same sector. If there are no competing theatres, then compare to wages for managers at fast food and other retail establishments.
Bottom line is that a manager should get a compensation package that at least includes health care, options for retirement plans, plus enough spendable income for decent housing, food and transportation, clothing, and other necessities such as child care. If you've ever priced health care as an individual, you know that the group health plans save employees big bucks.
Going into a job, a potential manager has to figure whether he will come out ahead or behind. I've turned down jobs where the figures just didn't make sense, and resigned jobs where the pay wasn't commensurate with the work.
I will say that the $400 to $450 a week figure was used by one circuit about ten years ago for starting managers, along with an excellent concession and benefits package. Given inflation and general increases in local taxes, I'd consider those figures a weak package in any metropolitan area, even though they might be quite good in rural areas.