I think some just went out of business.

It happened to me two years in a row. There were (at least) two local restaurants that I would pay a visit. By the time I wanted to use the coupons, one of them was out of business, and the other changed the ownership.

I notice the restaurant listings are getting less attractive every year as well. The Safeway/Randall's coupons used to be $60 (1 $5 coupon/month) per book. Now it's $20 (1 $5 coupon/quarter).