But I fear they are...
Do you honestly think people are going to sacrifice their KD ratios and chances at higher experience multipliers just to farm gold? If people are so afraid to lose gold that they refuse to wear decent gear, then they deserve to lose.
However, you seem to be under the impression that building for a x1 means a team will not have decent gear available to them. Even with an entire team gearing for x1, they still have more than a fighting chance if their players are skilled. For example, let me throw out a couple of builds that would lose no money at a x1, using the 0.0025 upkeep cost suggested in the OP (ie, under 20,000 gold):
Melee:Miaodao, Katana, Great Maul
Scimitar, Iberian Mace, Arming Sword, Military Cleaver + Elite Cav Shield, Heavy Round Shield, Plate Covered Round Shield
Long War Axe, English Bill, Long Hafted Blade
Broad Rimmed Kettle Hat
Heraldic Mail
Leather Gloves
Splinted Leather Greaves Over Mail
CavLance / Military Cleaver / Heavy Bastard sword
Rouncey
Spiked Cap
Lamellar Vest
Leather Gloves
Leather Boots
Archer:Horn bow
2x bodkins
Pickaxe
Light Leather Armor
Leather Gloves
Leather Boots
Xbow:Crossbow
Steel Bolts
War Axe / Fauchard / Yanmaodao
Footman's helmet
Lamellar Vest
Leather Gloves
Leather Boots
Obviously these are just examples, but they demonstrate what's possible. I think your fears are both unfounded and do not have the player-base's best interests in mind. Realistically, map balance & team balance do and would continue to play a much greater role in determining the outcome of a round than gear selection. Gear selection would also be unlikely to fluctuate terribly from what is used currently, as many people build for personal taste over min-maxing. Finally, even if people DID begin to design gearsets to take advantage of higher multipliers, it would only help to curb the huge amount of gold flooding the game.