Not that any of my clients would do this (or, candidly, I'd fire them), but suffice it to say I've heard of places where you can make enemies by being a wee bit too effective at plucking low-hanging fruit like this.
I think 9 figures is likely to be an exaggeration but say it is 7 figures (or low 8 figures) per year, which is probably pretty easy to verifiably achieve. Large corporations being what they are, there's a high probability that someone will be personally identified with the decision made 5 years ago which a) you're suggesting reversing and b) you're suggesting cost the company ~$40 million dollars. This combination makes you a threat to that person's career. Likely as not, that person is a VP, and they didn't get where they are without having political capital and favors owed to them by people who also might have eventually risk getting demoted for gross incompetence if that were possible to do with "mere numbers." So you have to watch your back.
I once had a consulting proposal where I suggested that a process change could improve outcomes by let's call it $X0 million (and I was charging $X0k). Apparently a VP had sponsored the current process, at a cost of $X million, and he was directly in the line of signatures required to get the consulting gig approved. That ended that.
Startups/small companies aren't immune to this sort of pathology but you tend to get a lot less of it in my experience.