no, the original 1/1000 odds that your first pick was correct (or conversely, 999/1000 that you picked incorrectly) remains the same even after elimination simply because there were that many choices at the start. that is, your 1/1000 chance does not improve to 1/2 with the elimination of incorrect choices.
if you make a choice *after* elimination, then it’s 50 50 because the door you may have chosen prior to elimination may be eliminated. but since you chose prior, it’s 1/1000 that you pick the right one and 999/1000 that you didn’t. 999/1000 odds that you chose incorrectly, given the removal of 998 doors, it’s almost a certainty that the remaining door that you didn’t chose is the winnar.
