[azernik]

The problem is not at all like restaurants. If a restaurant gives someone good food, they'll stop eating and buying today, but will probably be back tomorrow or later in the week.

With a dating site, if you're successful, you probably won't be seeing that customer again for at least several months, possibly forever. Sure, new people are entering the dating pool all the time, but the marketing effort required to constantly replenish your userbase at those levels of churn is incredible.