""Episode 4" did start it all, even if under a different name."
Luckily that is totally incorrect. It was released as Star Wars, nothing more. Star Wars started it all. The original theatrical version is available on the second hand market as laserdisc and special edition DVD bonus disc. I believe VHS also. If you watch it you will see only Star Wars appears on screen. Empire and Jedi do have the episode titles, as by that point Lucas was well running amuck. Also note, no episode titles on any merchandise or toys of the time, that I've ever heard of or seen, if further proof was necessary.
A lot of films have name changes prior to release, they usually use working titles, like blue harvest, or are charged for other reasons like Revenge of the Jedi. But they are not the real names of the released films.
Star Wars may well have been a flop, which would be bad enough without having a regrettable episode 4 stuck on it hampering it's use. So, the reasons are sound.
Another example is Master and Commander, the far side of the world. There is a reason it's not called episode 10 (from memory it was the 10th book). As that would be daft for a first film, and as it unfortunately transpired, it is the only film in that series.
There is a very good site dedicated to the subject of preserving the original theatrical versions if you have a search. Apparently Lucas even tried to swap the national archives original copy with a special edition version, the cheek!
It's good to be very clear on such things as the less initiated may not understand and that can perpetuate the problem.
The film released in 1977 was called Star Wars.
Future generations should be able to see it as it was originally released. Let's make sure it's not forgotten.
Optimus prime was the leader of the Autobots. If Churchill was the leader of WW2, he just sucked, as his troops were fighting themselves. If you write trivia questions remember to get your facts right.