This is a monster thread so I haven't read all the replies.
In case any failed to mention it, you get very frequent renown drops (the kind without opening chests or end rewards)
just for being grouped with your fellow guild members.
I have done my share of pugging, and I have floated around guilds to know that "many" players do not group with fellow members.
If you were to do this you might be surprised at the difference that could make. The current system of guild decay is
only part of the problem from reaching higher levels. The other part of the problem lies in leadership.
The rules are what they are, and they are attainable. You are an active player and on frequently, but are you an
"active" leader or a "casual" leader.
You might try grouping with a casual player when you see them on. Instead of the "Welcome to the guild. Now go
do your own thing to make us bigger." style of invite.
IMHO there is nothing wrong with the rules of the game, just the players.