In the original, switching is a better option because:
1.  You are wrong on your initial pick 2/3rds of the time.
2.  You never know when you are wrong initially.

So if you have a 2/3rds chance of being wrong and no way to eliminate the door you picked, then 2/3rds of the time the other hidden door will be the one with the car.

EDIT:  Let me put it like this, if you always choose Door 1 then two out of three times you are getting a goat on your pick.  Since it is impossible for the revealed goat to be a car, then the other door has a car.  The only time switching loses is when you picked the car to begin with.  That only happens one out of three times.

WARK!

Thus Spoketh Winterclaw: a blog about a Winterclaw who speaks from time to time.

 

(using Poser Pro 2014 SR3, on 64 bit Win 7, poser units are inches.)