I think in almost all cases it is just used to reward (or more likely) punish employees through pay or continued employment. I don’t think they actually care to improve their products, processes, etc.
TLDR if you don’t give all 10s the employee gets in trouble and eventually fired, even for things not in their control
The McDonalds near me hasn’t had ice cream in a year. I reported them to corporate and they had ice cream again for like two weeks until they claimed their machine was broke again