Part of the problem may be a perception issue. Here's what I mean. I see 59 posts in the ISO/Requests forum in the past two weeks. Of those, I count thirteen that are actual requests for services, rather than an ISO for details on a specific girl or ad (not counting one who was looking to sell old Playboys).
http://www.eccie.net/showthread.php?t=421326
http://www.eccie.net/showthread.php?t=420340
http://www.eccie.net/showthread.php?t=420079
http://www.eccie.net/showthread.php?t=419510
http://www.eccie.net/showthread.php?t=419120
http://www.eccie.net/showthread.php?t=418425
http://www.eccie.net/showthread.php?t=417624
http://www.eccie.net/showthread.php?t=414832
http://www.eccie.net/showthread.php?t=414813
http://www.eccie.net/showthread.php?t=414766
http://www.eccie.net/showthread.php?t=413402
http://www.eccie.net/showthread.php?t=411556
http://www.eccie.net/showthread.php?t=306021
Of those, only ONE (the last one, about Topeka massage parlors) had any meaningful or useful responses posted in the forum. Some of the others had responses posted, but at best they were "Do a search" and at worst they were jokes or taunts. Most of them had no responses in the forum at all.
Does that mean that none of them got any responses at all? We don't know. They could have gotten private messages and we would never know. Even that previously mentioned "$100" request could have turned up plenty of ladies who were willing to go visit the guy, and we'd never know.
So, not only are legitimate requests only a small portion of the total posts in the forum (22% of posts), but they don't APPEAR to garner any real results. Perhaps more people would try this method if the original poster would return to his post to say "Thanks to the offline responses I did find what i was looking for, and a good time was had by all."
Basically, I agree with lakecat that the problem is the smaller KC market. We don't have a huge pool of ladies who are competing for business like the do in Dallas. Until guys find that request posts have a result, there is not much incentive to make them.
EDIT: Note that these numbers are only for the ISO/Requests forum. They don't include posts like
this one right here in Coed Discussions which seems to have worked exactly what we would want.