This is because many top European clubs would like to win the Champions League every season. It is not easy, the competition is big, and each of these clubs has excellent players who can make the difference. Details, the player's impulse, decide, so betting on a given team to win the Champions League is wishful thinking. Of course, you can count on victory, but it is very difficult, and very often luck also decides. Even if the club spends an infinite amount of money, it will NEVER have a guarantee that it will win any title - this is sport and anything can happen here.