The champions league is all about money, let's face it most teams want to qualify for it because of that reason. Nobody is interested in the Europa, the FA cup or the LC because the reward is so thin and doing well in the PL well, let's face it, once the title is decided it is all about top 4 and relegation (ie the money)
Do you watch Brighton v Burnley? Probably not, it's the elite English league but does not pull in viewers, do you watch Krasnovar v Rennes?, again, probably not although it's the elite european competition group stage. A lot of people won't watch those games and, aside from watching your own club (Real Madrid have 36.5m twitter followers, Krasnovar 225k) you may be pulled in by games like PSG v Barca at the most. If no one watches then the advertising revenue goes down. If the revenue goes down, the whole thing collapses.
It has nothing to do with football these days, football chose to dine at the devil's table, the devil does not work with ethics and principles.