The 'dibs' system worked fine for more than 13 years of chip sales on CT, HPT, and PCF (2005-2019 or so). It was never exactly fair to casual forum users, as 'first-come first-served' sales required being actively involved and frequently online in order to see and accept sales offers. It was certainly open to misuse, but those rare occasions were quickly identified and dealt with harshly by the membership at large. And so it worked..... mostly due to the honesty, integrity, and friendship shared by the vast majority of the community members.
It's the latter aspect which has changed. With a significant increase in membership has come a larger number of people who do not view the forum as a community, but rather as a place to either make a profit, or with no personal ties to anyone resulting in a 'me first at all costs' approach to chipping. Both violate the longstanding traditions of this once-small brotherhood of small clay disc collectors.
The percentage of members is likely similar to those in the past, but the sheer volume of new members in recent years makes the actual number of non-community-minded members significantly higher than before. And that's where the old sales system starts to fail -- when a large portion of the users try to find ways around the system to either maximize profits or 'get what they want' without any regard for others, rules, or fair play..... while the vast majority still operate under the assumption that those types of things simply aren't done among friends in a common community setting.