Walmart is in business to make as much money as they can. They owe it to their owners/shareholders. That is their reason for existing.
So they will naturally want to maintain their present level of profit. If they do not, their stock will undoubtedly shrink. Possibly drastically.
If they pay their employees more money - then they MUST raise prices or lay off people or both.
Just making a small profit is not the point of running a business.
Making as much money as you possibly can in a legal/ethical manner is the purpose of running a business.