The OKCupid model doesn't have the same short-term profits and/or VC returns as desperate people shelling out for dating app subscriptions, so nobody will fund it.
At that point you're down to real users who are jerks, the solution to which is the block button and a message sorting algorithm that takes into account how many times it's been used against someone.
Now tell me all the reasons you won't do it.
As to why I don't do it, maybe I will -- but I wouldn't object if someone beat me to it. Because it still requires some combination of time and money, the amount of which can be feasible without being zero, and it's quite likely that of all the people in the world, someone who isn't me is in a better position to pull it off before I do.
This isn't going to be bring in anywhere near the amount of money you're thinking it will.