That doesn't account for the good-will and word-of-mouth generated from any successful matches, which presumably could lead to many more customers than those lost due to marriage.
That's a very difficult metric to measure whereas "did this user return and continue paying" is easier. The tyranny of metrics in action.
I feel like that kind of word of mouth is not enough to compensate. Like how many customers is word of one sucessful match expected to attract?
Very anecdotal, but in my experience people have no attachment to or enthusiasm for dating apps. I've heard (acquainted) couples say the met on dating apps. No one ever said which ones.