Here in Georgia, maybe 10-15% of membership comes to lodge meetings regularly at the lodges I've attended.
Informal
chats I've had with many members outside of the lodge all indicate the same reasons they don't attend:
1. They get nothing out of it. The meetings are unilluminating and boring.
2. They have or had a personal quarrel with another member of their lodge.
Interestingly, almost all the Masons I've met who don't attend lodge continue to pay their dues so they can "belong."
Widow's Son
BurningTaper.com