I believe private for-profit companies exist for the purpose of making profits. So I would say it ultimately does begin and end at the bottom line. If my hypothetical company decided to make the $9 profit product instead, it would only be because they anticipated a costly PR nightmare if they went with the $10 product. It always comes down to the financial bottom line.

So do you make more profit with the $9 product as is, or the $10 product with possible recalls, legal problems, and fewer future sales with an angry customer base?

Thus the self-interest is both concerned with the bottom line and doing the "right" thing.