Loyalty and win-back programs judged on incremental behavior, not on members who were going to buy anyway.
A fixed lapse window reaches monthly buyers a month late and interrupts quarterly buyers who were never gone. Timing win-back to each customer's own interval, and splitting it by why they left.
Loyalty reporting compares members to non-members, which measures who chose to enroll. The only comparison that measures the program is a randomized holdout, and it usually returns a much smaller number.