It keeps the game from getting stale, too. So active guilds are always attractive to active players, it forces the parts of the metaphoric chess board to make a move.
I can relate to your fustration - by the way.
However, the alternative is the previous version that we know of; no guild points, unlimited member cap, you will just see 90% of the server sat in the same guild for years, dominating the game. All high level, inactive players just sat in there waiting to log in and crack on again. Its been tried & tested.
A lot of work went into this guild system and it is as zade said an engaging part of the game - as long as you are not left carrying the cross all on your own.