Not so. The point isn't to differentiate yourself from everyone else (hence why who else does it should be immaterial), nor is to be a bit of pablum served up to your shareholders (as the 90% mentioned here is), it's to be a set of clear priorities to help decision makers make decisions.
Again, going back to the J&J case, placing their priority on their customers, their community, above their employees, and above their stockholders, meant that everyone could align in "We have to do what is safest for them, despite the cost or inconvenience to us". It would have been much easier to just issue a localized recall; they instead issued a national one. They could have pointed fingers (the addition of cyanide was, after all, not their fault); instead they took ownership over how to make their product safer. Etc.
It's not a catch all or magic bullet, but it -is- important to know, when making decisions, what to prioritize for.
You might want to look up J&J's handling of warning labels on over-the-counter painkillers, specifically re: Stevens-Johnson Syndrome, before you let yourself become too enthusiastic about their corporate values.
I'm not actually extolling their virtues as a company, just pointing out a case where a set of values led to an action that would otherwise have not happened, and which actually led to a long term benefit.
Does every/any company adhere consistently to that? Of course not; companies are made of fallible humans.
But how do you -ever- bind a group of people together to pull in the same direction, -especially- when it's at the expense of short term gains, for unclear long term gains? By creating a guide, a set of principles. That's what a mission/values/etc statement is supposed to be. Not just marketing bullshit, but something that helps determine what action to take. "We're gonna be the best" isn't useful, "We're going to prioritize X" is; it's a guiding star to recalibrate against. Yes, it takes someone to point out when you drift, and corrective action to be taken, but without it, you have no hope whatsoever of staying on a given course.
Actually, they were told by the FDA they only needed to do a recall in the Chicago area, and that they were not legally culpable (because of course they weren't). Their actions in no way prevented frivolous lawsuits, and they were not going to actually have any won against them for some random person spiking their product with cyanide.
Instead of doing the minimal amount they had to do, they took it a step above. It would have been perfectly okay, and business as usual, to recall in Chicago, and then to do nothing. Instead they did a nation-wide recall, and didn't reintroduce the product until they had a solution to prevent it from happening again.
Let's not belabor the conversation, but I think there were more organizational factors in play than that. Most obvious, think about the damage to the brand if consumers associate it with cyanide (of all things). The only "value" at play there was organizational and career self-preservation for the people responsible for responding to the incident. I highly doubt there were any noble impulses or high-minded values involved.
I don't have the case study details in front of me, but just as an aside, companies can be sued and will lose if the plaintiff can prove they were negligent; for example, not taking reasonable steps to prevent tampering.
I think you could kind of generalise this to say that a mission statement is only useful if you can imagine some situations where someone would have a difficult call to make and could reference the mission statement to help make the decision.
The one I always think of as good is "Move fast and break things". Not that it necessarily is a good idea, but rather that you can quite clearly use it to help make decisions like "do we launch now to capture a transient opportunity or later to ensure full QA?"
Again, going back to the J&J case, placing their priority on their customers, their community, above their employees, and above their stockholders, meant that everyone could align in "We have to do what is safest for them, despite the cost or inconvenience to us". It would have been much easier to just issue a localized recall; they instead issued a national one. They could have pointed fingers (the addition of cyanide was, after all, not their fault); instead they took ownership over how to make their product safer. Etc.
It's not a catch all or magic bullet, but it -is- important to know, when making decisions, what to prioritize for.