Oh, of course. I'm not saying you should run headless into the first war that presents itself. Every realm must be careful in deciding which war they will join, or they'll find themselves weaker after it than before. But not all realms are equal, and that is the normal state of the game.
A realm always finds itself in the situation it is currently in. The reason you are wary of war at the moment is because you know that if you remain at peace, you will be stronger three months down the road, therefore your baseline for going to war is higher than a realm which will find itself unchanged if it does nothing. However your ability to go to war is not impaired, it is at a certain level and that's it. Find an objective worthy enough and you will be able to go to war.
Said another way, you currently have a city and a half. It seems you would feel better if you had two cities. Do you know what is a fast way to get a second city, faster than waiting for Oroya to repopulate?
Invade one.
While that is true, in a sense, it is also impractical considering all the other realms around us, with the exception of one, are stronger than us. I am not complaining, that is to be expected. When a realm starts, it doesn't start out as a Perdan or Sirion that can war with whoever whenever for whatever reason.
Also, gold isn't the only thing realm's need from a city. Cities hold infrastructure as well, and a solid infrastructure is needed to win a war. We could theoretically fight a war right now, but if we don't have the infrastructure down, it's going to be a short war. And if we fight a losing war, or even a war in general, with a weakened city, there is a chance, a very good chance, that our enemies could take advantage of that fact and reduce it again, or take it. But to make a city stronger, you need to wait for better population and more gold, and those things are tied together considering this is a region that is a gold producer.
Going to war isn't just about gathering new assets. It's about defending the assets you already have too.