If you look closey at a bald head, it's not really bald but instead there's just really tiny 1-3mm vellus colorless hairs there instead of normal "thick" head hair. In fact these vellus hairs look exactly like inner ear hairs.
I think the hypothesis that DHT is the cause of hair loss is wrong, instead I believe that something goes wrong in the β-catenin, Lef, Wnt system which causes your head follicles to inadvertently produce ear hair instead of head hair (obviously there's no nerves attached so you can't hear from them).
Unfortunately though playing with the β-catenin, Lef, Wnt system can easily lead to tumors which makes finding a cure extremely difficult.