Gamespoet. Why insist on having the regimental colours in silk when you can have cheaper cotton? Because your soldiers would have felt humiliated and in full fury of being treated like dirt by not being given a proper banner out of silk.
There is no opposition between showing status and combat. The present day situation is probably just a temporary thing. We tend to understand and view everything from our perspective, but the fact is that throughout most history the norm seems to have been an eagerness to show of status and prestige on your own wargear!
A roman legionary would probably have disliked the present attitude towards personalization of a soldiers kit. The longer he served the vet would tend to "bling" out his kit more and more. And yes, he would fight in it.
Why fight in your fineries and risk having them trashed? Simple. Because by fighting in your fineries and risk them you show your enemy that:
1. You are a badass soldier who have fought long and survived to earn some handy extra coin enabling you to bling out your kit. You gotta be pretty darn though.
2. You show you are not scared one bit about him ever getting close to ruin your fineries.
The romans managed to achieved a rather neat esprit de corps and look of unity in their units while still allowing for personalization. And many see the romans as probably the most disciplined and most military army in history, even surpassing many modern forces.
Much comes down to the social standing and status of the common soldiers too. And to the level of individual involvement in contrast to state control over warfare.
And in the end, modern soldiers
do bling out their kits and their vehicles as much as they can within the given restrictions. If things would be more free, you might see engraved cannons and gold engraved assaults rifles.
And you know what? I believe we will sooner or later turn back to that. And remember the german uniforms of WWII. Designed by Hugo Boss. Damn sure they were not the best adapted fighting dress in WWII, that gotta have been the US or maybe the british battledress. But damn did they look mean and sexy.