Bottom line is that majority rules when it comes to older content like this. You can't force people who don't want to watch cutscenes to wait at boss fights for you to read everything then catch up. You can however view the cutscenes again after the dungeon if you go to the inn room, they're under the duties category.

The reason people can do the dungeons without you is because it's old content from launch and they are vastly overgeared for that content now.

That said however, SE saw the flaw in this design fairly early so aside from CM and Prae there really isn't any endgame content with long cutscenes during the dungeon. Most of the long cutscenes take place before or after most of the dungeons following CM and Prae.