I have a theory:
It's kind of like undercover cops and the "color of the day" (so they can identify each other).
In Starfleet's case, it's to make it just that much harder for enemy infiltrators. If they don't have the latest info on Starfleet's current uniform style - and many don't - they won't know what Starfleet uniforms currently look like.
Thoughts? I realize I'm reaching here but it's the only explanation I can find as to why Starfleet uniforms change so damn much.

It's kind of like undercover cops and the "color of the day" (so they can identify each other).
In Starfleet's case, it's to make it just that much harder for enemy infiltrators. If they don't have the latest info on Starfleet's current uniform style - and many don't - they won't know what Starfleet uniforms currently look like.
Thoughts? I realize I'm reaching here but it's the only explanation I can find as to why Starfleet uniforms change so damn much.

