Earlier quoted context omitted.
Funnily enough, by your wide standard, any footwear would also be considered a vehicle.
That would depend on your definition of "carry." I personally wouldn't say that shoes "carry" people any more than floors do (which is to say, they don't).
I would say those two things are very different. The ground (floors are inside) is the cooperating object upon which leading objects carry.
The shoes carried the person on the ground, the car carried the person on the ground, the horse carried the person on the ground, etc;
An interesting dilemma does occur if we are walking barefoot: our feet carry us but are part of our whole, so we cannot reasonably consider them or ourselves a vehicle. But in a general day-to-day sense we would say they carry us.
It is very interesting what you brought up because I think it shows some people consider their outfit as an extension of themselves. Then again, many people also do for their car :)