Talk about misaligned incentives!
The dearth of effective dating platforms is the expected end state of the current "pay per use" model. The popular sites earn more from repeat customers than from single-time customers. That is fine for general goods & services. However it goes against the usual idea for dating: to find a partner & establish a good, lasting relationship in as few "attempts" as possible. Users successfully coupling up are effectively "lost" for the platform that facilitated it.
What would it take to build a sustainable dating platform? First up, it would need to benefit the most from a successful & permanent match, rather from repeated use.
As much as I dislike Facebook for their abysmal handling of privacy, I figure FB Dating suffers less form misaligned incentives than standalone dating platforms. Presumably users will remain on FB proper anyway, whether their dates are successful or not.
Come to think of it, the "traditional" (for lack of better word) society built on nuclear families just might have been geared that way - to benefit the most from people finding partners & becoming long term couples.