That's because the baddies tend to be Fighters and Rogues more often, but most of them definitely have members in that number, even for small and relatively unimportant enemy groups that would be encountered in a level 7ish adventure (to scale it down just a bit--in a level 3ish SCAP adventure, a minor and relatively worthless group of goblins had ~10 4th-level Adepts and many more combat-centred goblins).
A dragon may have more going for it than SR and AC, but none of that will protect it from an at-will touch attack attack that deals force damage with no SR allowed (though remember, this is hypothetical, as currently we have a quite fine non-touch attack force effect). Obviously it can sit in its lair behind layers of traps, but these guys would be effective in preventing it from going on the offensive.