If Eliezer had written the antimatter ending, it would indeed have implied that Voldemort would later take over the world, since the antimatter would not have been able to destroy his horcrux network.
To follow up on this, the sad ending wouldn’t be the sad ending because Harry had to sacrifice himself to win. It would be the sad ending because Harry failed, as a result of not being able to think of a clever enough way to stop Voldemort (reflecting our own failure to do so in the exam).
If Eliezer had written the antimatter ending, it would indeed have implied that Voldemort would later take over the world, since the antimatter would not have been able to destroy his horcrux network.
To follow up on this, the sad ending wouldn’t be the sad ending because Harry had to sacrifice himself to win. It would be the sad ending because Harry failed, as a result of not being able to think of a clever enough way to stop Voldemort (reflecting our own failure to do so in the exam).