You wouldn't have a lot of happy buyers - you'd have far fewer. You are assuming that everyone on a dating service has a good match on that same dating service, which isn't the case. From the business side you have a choice, get a small amount of money from most participants or get a large amount from very few. Even if the totals are the same, the latter is far more risky.

There are quite a few human run expensive dating agencies. It is what rich people use. This one for example costs about $100k to sign up.

  http://www.orlythematchmaker.com/

An article from a few years ago titled "Professionals pay matchmakers to be headhunters for the heart" about expensive human run dating agencies:

  http://www.usatoday.com/life/lifestyle/2008-02-12-matchmakers-main_N.htm