It is in Fox's best interest
It is in Fox's best interest to keep it's viewers of this show.
It is in Fox's best interest to keep CKTD around to make it interesting and to keep the fan favorites.
It is in Fox's best interest to not allow the Amy & Co. to eliminate one by one CKTD alliance or viewers will get bored and discouraged.
It is in Fox's best interest to let the good guy or/and girl win IF they want viewers to watch Paradise Hotel 2 next summer.
It is in Fox's best interest to create twists that will keep us guessing and not be too predictable and have the 7 eliminate the 4 and then turn on each other with "no hard feelings" response with a tone of respect.
Like every good story or movie out there, the nice person, fan favorite, hero if you may, wins in the end. Everyone feels all warm and fuzzy, and appreciate these kind of shows where good overcomes all odds and prevails over evil. What comes to mind here is Lord of the Rings trilogy.
IF Fox has complete control over this, they should KEEP it interesting and keep our heroes in the game as long as they possibly can so WE can have someone to cheer for. What is the use of watching this show if all that remains are people that disgusts us with their behaviors. Not too curious to tune in if all that's left is Amy, Beau, Scott and Holly and Desiree. No thanks.
You have a formula that works, don't change it.