Madrid was only concerned of their attacking force, they forgot that only strikers cannot win the matches for them. Only Mbappe and Endrick was signed into the club after thet won the Champions League last season. This should be a lesson for Madrid management that they need to solidify all areas of the team if they want to continue winning trophies like they did in the past.
Yes they were only concerned about improving their attack forgetting that the defense is the heart of the team and when the defense is not strong no matter how the attack performs all their efforts will be easily cancelled out. They have learned their mistakes now and I am sure they will not want to repeat the same thing because of the humiliation they experienced this season in the hands of Barcelona and also losing to Arsenal was shameful, a team that has no experience in the champions league.
I see how desperate they are now to sign defenders even before the season ends, they got Arnold already and they are linked to Romero and Bournemouth defender which is a very good thing. If they can improve their defense they should be back to their winning ways.
To be fair, they didn't expected their centre backs to get injured in rotation and their only decent right back to close the entire season. That was an unexpected situation, plus Mendy spent a lot of time injured as well. So between injuries that lasted all season, and injuries at the same position in rotation all the time, they ended up with not having to play with their best defensive players in all positions at the same time all that much at all, just at the start of the season.
When you look at it that way, you realize why they weren't ready. Now they got Trent for right back, and a new young defender, so even if there are issues with injuries, they have more alternatives this time and should be doing fine next season.