I don't think casinos will ever consider having such an option. Inasmuch as casinos might also be guiding and advising gamblers to gamble responsibly, setting such a limit won't be a thing for them. Let's not forget that casinos are businesses, and they are there to make profit, which means your loss for the week is their own gain. Setting up such an option for a minimum loss in a week is going to reduce their own earnings from gamblers.
Casinos are a business as you have suggested and as any other business their main aim is to earn money. This doesn't make them your enemy, they are just doing their job (business).
As a counter example, do you know that there are some casinos which will let you set an amount to gamble per day and if you exceed it they will notify you! Do you know that there are some casinos which will notify you when you have been playing for more than an hour or even less! Casinos aren't your enemy. You are your own enemy!