My infantry equipment:
Kettle Helmet
Byrnie
Mail Guantlets
Mail Chausses
Awlpike
Costs: 18,784 gold
To make it cav, add a rouncey and heavy lance
Cost: 37,496 gold
To have cavalry, with the second cheapest and first usable horse, itcosts me just under double my infantry rquipment. And it's not even heavy armour!
To use with a courser, which is the next horse I'd use (because I'm a western themed knight so why the hell would I use eastern horses?) It costs 48,324
That's the same as above but with a courser instead of a rouncey
As infantry, with 50k worth of equipment, you're unstoppable, look.
Great helm, transitional armour, shynbaulds and gauntlets costs 38255. This leaves you 12,000 to spend on a weapon, which polearm wise will get you anything up to the GLA!
So the balance of power is way out, as you can see.
So lower horse price a bit, because infantry can equip more than double armour for the same price!