As organizations become more complex, it's difficult to understand the consequences of many high-level decisions. Unless great effort is made to gather feedback, it won't happen.
Not only that: the lack of immediate, human communication results in one-way feedback mechanisms, like suggestion boxes and surveys. Many companies clearly want to make this work, because we're constantly prompted and sometimes paid to fill out surveys. But the result is survey fatigue.
The person giving feedback needs to be reassured (by people, not machines) that their feedback matters, or they won't be bothered to do it. Often, it's socially awkward to give negative feedback, so people don't. And often, the employees directly on the scene have incentive to encourage customers to avoid negativity when they fill out surveys.
One way to show that feedback matters is to respond to complaints with some sort of assistance. In the example in the article, that's a voucher. Perhaps somewhere in the organization, that voucher counts as a cost, but it's pretty unsatisfying.
In some organizations, managers are encouraged to work at the support desk occasionally as a more immediate way to understand what's going on. (I remember reading about how Craig Newmark would do this for his website.)