OP, (Uncertain of what the original question was)
Yes, the upkeep is necessary.
My Tincan's equipments: (Repairs are estimates)
Inventory: Great Lance (180), Steel Pick (410), Steel Shield (520)
Armors: Milanese Sallet (440), Milanese Plate (1550), Plate Mitten (540), Cased Greaves (210)
Horse: Plated Charger (3.3k)
If everything was broken at once, I'd have to pay over 7k of repairs each round.
But of course, nothing like that ever happened to me, only the occasional bad luck of having my milanese plate and plated charger damaged and repaired at the same time, my repairs were from none to around 5k.
The 'none' part, is when I don't die as often, the armors did their part of saving my slow reflexes against the hail of arrows or cuts here and there, but most lancers charging full speed at me still 1 shot me most of the time.
I'm not proud to admit being not very skilled at cavalry nor infantry, but I like role-playing/supporting as a full plated knight, not some cheap mercenary looking for hire. The upkeep, however, kept me from wearing my full plate equipments every round; which is fair, because without all these armor, I would be almost unable to keep my k/d ratio positive at all.
As I hate to say, the upkeep is necessary to keep the fields clear of not-dying-fast-enough tincans like me. I've just caused some round draws earlier and I'm not fond of it.
Edit: So I pretty much agree with this
Edit: And the reason why upkeep exists is for the precise reason of keeping people from using the best equipment exclusively. Before upkeep was implemented, the game was even more impossible for new players since veterans would walk around with the best armour. So this is really for your own good.