Because most Superhero films have been trending downward overall in International markets for a few years now. Pre-Covid the International Market was huge for superhero films, China being the biggest one. Man of Steel grossed nearly $65m in China alone, and then Aquaman did $300m over there. But China doesn't give af about CBMs these days, and the rest of the world is following suite.
You've brought up Deadpool and Wolverine twice now. That movie was an event level film. Hugh Jackman's Wolverine is quite famous, and people turned up to see those two characters in a film together. Same reason people turned up to see Tobey, Andrew and Tom interact in Spiderman NWH. Event films have a much bigger hook to them than a solo film. But this year we had three CBMs that got great reviews and great wom, and overseas didn't show up like they used to. There's no assumptions being made here, it's just pure data. Overseas have lost interest. They don't care whether or not a movie is good. Look at the Jurassic World movies. Terrible films, but people want to see CGI Dinos, so they do great. Then look at recent CBMs. Even the ones that got good reviews and word of mouth, people aren't showing up like they used to. Pretty obvious what's happening here.
People need to realign their expectatoins with Superhero Films. This isn't the Marvel Phase 3 Era anymore, where any superhero film can breeze past $800m easily, and even hit $1b. The Superhero craze of 2008 - 2019 is over. The average CBM is making $400 - $650m these days. We're back to pre-Iron Man market with these movies now. Video Game films are looking like they will be the next big thing.