I have not seen many examples of Hollywood movies shown first in the rest of the world before the USA, but it is certainly the case that simultaneous release around the world is now normal when it used to be rare. If the trend has continued beyond 'simultaneous' to now opening in the rest of the world first, it is probably for the same reason.
There are several factors affecting this, for instance with digital technology, it is becoming easier and quicker to distribute movies. However the main reason I think is preventing piracy cutting into profits.
It used to be that Hollywood movies would be released weeks or even months before release in the rest of the world. I think this partially came down to hitting the biggest market first and building a reputation before going abroad, but it also used to be very hard to pirate a movie. You would have often to film a movie in a theater, and the quality would be normally pretty bad.
Nowadays, with vastly better technology, it is far easier and cheaper for high quality copies of movies to be made and quickly distributed worldwide. Studio's have to hit the worldwide market much faster to prevent pirated copies of the movie diluting their profits, especially around the world.