MY COMMENTARY:
There are no average customers. If there were average customers we never would have witnessed the exponential growth of current main line businesses such as FedEx, Amazon, eBay, and others, who began as niche businesses that analyzed the potential markets beyond simple averages or generalities.
As I have noted in the past, the key to any loyalty program of value is to understand what the consumer values. While price is certainly an element in any such program, it tends to make the customer one dimensional. If there are no average customers, then it seems to follow that a loyalty program based solely on price goes against the grain of no average customers.
Shopper behavior does vary. The key is to identify the factors--beyond price--that marketers can use to continue the loyalty of current customers.