So that's the reason as guys age we end up hairer on our bodies and end up walking around like bald gorillas.

Let Me Wikipedia That For You https://en.wikipedia.org/wiki/Pattern_hair_loss#Causes

riding around in convertibles.

I just got too tall too fast. Grew right up through my hair!

The hair gremlins wake us up if they try to pluck our facial hair

It takes too long for the stress to work its way down.

As a very bald man, let me assure you, hair does not merely keep growing other places. The exact same hormones that cause the baldness make it start coming out of unexpected places like weeds in a sidewalk. So cool. /s

As to why hair follicles work backwards specifically on the very top tip of genetically predisposed individuals, I can't say. There's a lot of information on the Wikipedia, but probably more we're yet to discover. I know it's still an active area of medical research. Especially active, even, because it's an old white/asian guy problem (usually).

My understanding is it is hormonal and governed by androgens, testosterone, and DHT. Depending on a man's levels and how sensitive their follicles are, it will affect how their scalp or beard grows. It can also be genetic/inherited and they are more likely to bald as they get older. Medication is usually aimed at hormonal causes and combined with something like minoxidil, which is a vasodilator.

Women also go through something similar, except the beard part for most women.

Big Hat

Something about it being different kinds of hair. Facial hair trend to be more "pubic", with it's coarseness and waviness. If anything, as men get older, that kind of hair grows more vigorously.