Nope. Think about this.

He opens one door and asks you to choose again. You're not going to pick the open door so of the doors that you would choose from, there are only 999. Your odds change.

The logic you use works for all the doors that EXIST, not the odds of the doors you will consider choosing. I'll take the odds for doors I will consider choosing because it increases my odds. But in the end, when there are only two doors left, the odds of you choosing the winning door of the two is 1/2 or 50/50 or 50%.

>The point is that after you picked a door he opens 998 doors where there is no car ( - he knows where the car is). That makes the odds of the last door 999/1000
>
>Think about it