Why most review programmes stall
The usual pattern is a burst of activity, a modest number of reviews, and then nothing. This happens because the request is treated as a campaign rather than as part of a routine. Campaigns need someone to run them, and that person has other work. Requests attached to an event that already happens do not need anyone.
There is also a quieter reason. Asking feels awkward, so people ask only the customers they are sure about. That produces a small, perfect and slightly implausible profile, and it means the honest neutral reviews that make a profile credible never arrive.