Profit = income - expense. The other way to maximize profit is reduce wasteful operating expenses.

As long as your chasing profit not revenue expenses are already part of the equation.

If being open at 2am provides 1$ an hour of profit, that’s still profit.

It's questionable if you're going to get any profit at all when you have to pay someone to man the store at odd hours when there's almost no customers. A few people coming in during the late-night shift and buying $3 worth of stuff each is not going to pay that employee's salary.

Have you read the article? The franchise pushes the store owner to make it work anyway, and since the employee's salary would eat his profit, he cannibalizes his free time and sleep instead. The franchise contract is probably structured in a way that the franchise company profits even from stores that are themselves barely profitable.

Something I've often thought gets overlooked

And in a market where the parent company doesn’t protect area rights, your competition can be other stores of the same franchise. Something about that seems wrong.

Depending on how the franchise contract is structured, the parent company may profit from every store, no matter how little profit that store itself makes, because of things like having to buy supplies and equipment from the parent company at inflated prices.