We shouldn't assume that if all five-spot tables in a casino were suddenly converted into seven-spot tables, there would be players there to fill the additional spots. By that, I mean that if the volume of customers called for it and space was too limited to bring in more tables, you just know that some of the existing five-spot tables would be changed to seven spots.

Somebody somewhere probably figured out that they'd make more money with seven dealers each dealing to five players than with five dealers each dealing to seven players, even if it meant paying the salaries of two additional dealers.

It probably reduces the house's risk by having more dealers in play, too. Wouldn't profits be a lot more reliable (steady) with 70 tables instead of 50, even if the number of paying players is the same?