None of that has anything to do with anything in this thread. Nobody has talked about k/d or even win/lose income differences. They don't matter, only you keep talking about this. I don't know why it is hardly relevant to the actual problem.
It seemed to be the only relevant thing to say as what you said afterwards makes no sense :
You have to earn money by leveling up, you just stated why in the previous quote. By just standing afk and leveling/gaining gold you are earning money as you level.
You do not win
more gold by playing one minute at level 30 than playing 1 minute at level 1. You are purposefully playing with words to make a point.
The fact that you don't understand how someone with 1million dollar and someone with 20k dollars are effected differently by a tax that hits them both equally in borderline insane.
No it isn't. Your instinct and how the human brain grasps the concept of money are inherently flawed and illogical. Both the 1M guy and the ultra indebt -500k guy are able to buy things worth 10k less in total when they lose 10k. The only difference is that you suppose the 1M guy will not have trouble spending for his "needs", and the 20k guy will if they both lose 10k. But if both were perfectly logical entities they would give the same value for that money.
Why do you think people with higher income and lower income are taxed different in real life? Do you not understand how it would make more sense to make the upkeep% based vs your level in the least to help out poorer/newer players?
The upkeep is based on the assumption that everybody stays in the 27-30 level range more than half their playtime, which is a truism as the xp required for 30 to 31 is equal to the xp needed for 1 to 30. As the level field is extremely balanced already, upkeep does not need to take it into account and only makes a difference between cheap and expensive equipment.
Man you ought to try this mod back when reaching level 25 or buying your first decent weapon was an acheivement. People don't understand they aren't supposed to have even remotely equal stats as others to enjoy a game. Playing as a peasant is different and original. cRPG already is much more "fair" to new players than it ever was, if that makes sense. New players are destroyed by skilled players anyway, even when they have a big advantage in stats and equipment, and it isn't any more "fair", old players had a lot of time to train their skills.