Player hoping, is actually simpler than what you are describing and there is nothing we can do about it 80% of the time.
80% of the time a player quits (or plays less time), and therefore gets kicked from the top alliance. That alliance then sends invites, naturally to top players and get them for the simple reason of competitiveness/rewards/prestige. That goes down the ladder so much, that the whole game is affecfed. Ive experienced this from alliance 130th to 1st.
For the other 20% Its just a matter of the person, there are loyal people and non loyal. Hoppers and non-hoppers. Again, nothing much you can do about them. Most people play the game to progress, besides the founder/general and “a few good men” everyone eventually moves “up” or his game time changes/quits.