AZ:
Throwing money at the problem will work for those who have it.
If someone would announce publicly (and put up a bond) that there is a 100K reward for anyone who gets his daughter a shidduch, it will work just as well if not better on a case by case basis. I just don’t see why this is different than paying to get on a list. There is still the point of 3 dates being arbitrary, perhaps A date is better.
The problem is when you expand the rule to the Klal, not the individual who does so on their own accord (which is not a bad idea in any case).
There is no chiyuv to pay for effort when there are no results (as I pointed out earlier). At best it’s Lifnim M’shuras hadin. 3 dates is not a “result”.
If the issue is effort, then the cost should be for getting on the list, which already exists for many shaddchunim.