Problem is that if you want fair rules that apply to everybody, you need them to be clear and with a hard limit.I thought about that too, but the thing is, they're already applying the rules individually. Obviously someone is checking the threads to see whether there's been any word from the dev. This is just a matter of looking back at the prior progress statements to see whether they were false. If a dev isn't giving out false progress reports, which is what ICSTOR has done repeatedly, then the update schedule doesn't matter.
There is no doubt that this game thread is checked often, but staff cannot simply say "Meh, this seems abandoned, let's set it so.", otherwise they could apply the same feelings for other game threads as well... Some would get marked abandoned sooner and some later, and that would create drama.
Saying "Abandoned is when the developer does not communicate anything for three months in a row" is a reasonable amount of time and pretty clear to understand.
It is abusable, sure, but people should also think and inform themselves before throwing money at a project.
I guess you could add an additional rule saying "Abandoned is ALSO when a project has not been updated for a year." as I doubt there are devs that do yearly releases...