Historically, all empires either fall or morph into some other empire… and then fall. We don’t use the term “empire” to describe nation-states that much anymore.
Regardless of what we call some countries, they are still able to project power outside their borders, being it globally (like the United States) or regionally (like Iran).
But when it comes to having to defend their home turf, some countries are just not going to roll over for any reason.