>those "standing" forces were citicen called to the eagles with their own kit

Exactly why I hi-lighted "could afford to have."

Did you read anything OP wrote beyond the title sentence?

>Ok, I'm not a historian, just a history enthusiast, and not a pretty knowledgeable one at that, so correct me if I say anything wrong. Anyway, I always heard that one of the reasons why swords are so iconic in pop culture is the fact that they were really expensive to produce and tended to be more useful as backup weapons, specially in the middle ages. That's probably one of the reasons the weapon became so associated with the archetype of the noble knight, which helped it become so iconic.

I understand that, in the time of the Roman Empire, swords would be much more useful as a main weapon, because armor wasn't so advanced, but that doesn't explain how did they manage to outfit most of their soldiers with gladii. I mean, they're still swords, they still require a lot of material and a lot more work to be made than, say, a spear, which is already an amazing weapon.