I don't think you quite understand what I'm trying to say.
Light footman = fast, low upkeep
Heavy footman = slow, high upkeep
Light horseman = fast, low upkeep
Heavy horseman = fast, high upkeep
There is our inconsistency and so the light horseman is at a disadvantage. I could be the richest player in cRPG, but if myself (as a light horseman) fought another player of equal skill (as a heavy horseman), I would always lose.
You're a bit off on your pseudo numbers.
Light infantry: 20~25k.
Heavy infantry: 30~40k.
Light cavalry: 35~50k. You have to remember that a heavy lance is 10k and a courser, Arabian or destrier are 20k+
Heavy cavalry: 60~75k or more.
The thing is, most players will do better as heavy infantry because they can wear 20k more armor and sink 5-7 more points into if, wm or ps.
The heavy lance costs too much for its utility now. Its worthless on foot and the regular lance is just about as good in 90% of the situations. Its actual utility was nerfed by half, but the price wasnt lowered. Plus all of the light horses usually get one shot, and the rider killed while falling.