We are going off target
This is not about the benefits of 1 player guilds
This is about preventing/stopping inactive guilds, most of which are 1 player guilds.
I understand that small guilds are upsetting your
GUILD JUMPING but you seem to be targeting inactive players "per sec" ... rather than trying to improve the guild hopping experience.
When I first opened an email account ... hotmail.com routinely deleted inactive accounts after 3 months (or less). I opened an account with yahoo.com and have maintained the same account for 20 years eventhough I've not logged in for many months at a time.
FoE is a lifelong game or simulator ... it ends when you end. It's more about getting inactive players to return to the game than eliminating players who are inactive in the short-term.
We have a member in our guild who started in 2014, stopped playing and recently returned to the game (He was in LMA and is presently in PME).