You do not need to be a champion in the "Champion's" league, haven't needed to be for nearly 30 years, but now it is to be expanded to 36 teams in the league stages - over 90 in pre-qualifying. A team does not even have to be in the top three or four in its own league to take part as it can use its historical co-efficient. With their records Real and Barca could finish 15th and 16th in La Liga and still "qualify" over the second in the league.
They might as well just allow anybody who turns up to get a game.