Yeah, keep repeating yourself that. The Caf's mantra since 2014 at least. Barça post-Messi is not going to sink as low as Arsenal or ManUtd; easier Liga tbw.The only one I can think of that was incredibly succesful was Jupp Heynecks with Bayern(his 2nd spell)
I think Real's domination is done, not because of Zidane, but because of Ronaldo. People tend to forget that Real couldn't get past the round of 16 for 8 years in a row. Ronaldo's insane numbers created an illusion that Real was bigger than it was. And now that he left it is showing. Even if they bring Neymar/Mbappe they will still struggle to reach the heights of prior years. You can't replace a 50+ goal per season player.
As soon as Messi will leave Barca, the same fate awaits them.
Madrid hugely misses CR, but it's also about Floren not replacing other key players (and in decline) like Modric, Marcelo, Kroos, Benzema, etc. Plus a sudden dip in quality by Casemiro and Varane.