HMMMMMMMMMMMMMMMMMM even the first two lines of that link are incredibly confusing and intriguing.
Perhaps ехать/ездить are MUCH more related to English "ride" than we're giving credit. There just happens to be in place a structure where "ride" would NEED to be used if it can.
You ride a horse.
Ride a bus.
A bus goes (not rides).
I go.
You ride your but down the hill.
(any counterexamples anyone?)
So maybe the key is in the fundamental definitional semantic difference between "go" and "ride", except with a twist, that Russian requires the distinction.