In fact, I am surprised by the specific numbers, because even for Bayern, which are consistently successful in European competition, the income from the Bundesliga is higher than from the Champions League. Still, success in European competition is of great financial importance, as the difference in Bundesliga revenue between first and tenth place is only 21%, and the difference in European competition revenue between first and sixth is 200%.
With big clubs, being able to play in Champions League means a lot for them. It secures their finance and balance sheet for that season. If suddenly in one season, they can not play in Champions League, their income will be lower a lot. Even it is only at a group stage, difference of income is big already. If they go farther like Round of 16, quarter or semi-final, income from Champions League will be bigger.
Losing income from Champions League is terrible for big clubs which have big salary burden for their star players. After a bad season, they will get more harmful effect by being less attractive with star players. That makes them harder to convince star players to join their clubs when they have big demand to increase their competitiveness with new star players.
Consequences are a lot, not only income but related to a few seasons after that.