You, as a user of a dating app, are forever in a Nash Equilibrium with the dating app. When you find the love of your life, you delete the app forever. Therefore, everything the app does to help you find that person works directly against their own goals (user growth, “engagement”. subscriptions).
I wonder if there is an alternative business model which would put users and the business on the same side. Could you put a lien against someone's marriage, such that in order to marry someone you meet on HappyDating.com you had to pay the outstanding debt? Anything less extreme?
Hookup apps. Apps for non-monogamous people. You're looking for repeat customers.
The only other way is paying when the couple gets into something long-term, but the fee would probably be higher than people want.