It's true that they never miss the UCL, in fact every year they always bring in top players, their finances are stable which makes Madrid always the strongest candidate to win the UCL every season, this is what all clubs should set an example to be able to maintain the club's finances so that they can Competing with big clubs, Barcelona should have to follow the example of its rivals in financial matters so that it is stable under any circumstances, it is difficult for Barcelona if financial matters always concern them because the problem lies there, so whatever happens Barcelona still has to compete even with current players. At least Barcelona is always consistent in any league so that they always get a pot of money from sponsorships or player sales.
Yes, Madrid is one of the teams that always participate in the Champions League, they have quality players from the beginning and the team has made name that make it a favorite for all players. To achieve such greatness is not easy for any team because they need money to do make such moves for players of higher caliber.
Real Madrid's financial stability is with the help of the bonuses they do get whenever they win trophy, and for them to be the best club in the world they are signing players of higher caliber and do get huge profit while selling them; but Barcelona started having issues since the departure of Messi which is not proper and I blame the management for going financially unstable for a big team like Barcelona.