Remember why distinguishing uniforms were developed in the first place. In the fog of war, even in the age of sail, you needed to see who was who. Not merely who was friend or foe, but who was in charge and who had the answers when things were FUBAR. The fact that even the most egalitarian of militaries maintain distinctive dress between ranks is an indication of rank (even in dress) matters, just as much as the rank itself.
My dress has been impeccable and well maintained since before I took the King's Shilling. Why? It was drilled into me as a child (who was poor as fuck) that people judge you first on your appearance, then your performance. Is it right? No. Is it the way things are? Yes.
The clothes make the man after all. When your position and status demand a higher standard of dress, you lose credibility if you look like a slob to your superiors, peers, and even to your subordinates.