It is hard to find members, and like you said, not a lot of clans can let go of is clan and money invested and merge with another and go into this state of fighting for a lost cause, unless there is incentive to join the game it will tend to be less and less active players over time.

To me there should be some kind of way in the game to seek and talk to other clans in order to merge themselves, but this topic should do a little help.
Good Luck