Per the friendly article, Walmart has spent over $1 billion total on this (fine, legal fees, investigation), which is a noticeable number even by megacorp standards.
Legal and investigative fees are not “massive fines.” Those are optional. They could have admitted guilt 10 years ago and not had to pay them.
And, speaking of 10 years, they had that long to spread that billion dollars over. They’ve probably made $300B in that time. $1B is a drop in the bucket.