Board Thread:General Discussion/@comment-26170720-20150307011059/@comment-10993019-20150307213851

It'd be interesting but way too complicated to explain IMO.

I'm fairly certain the only reason Ace Combat moved to Earth is to make it more relatable to new players unfamiliar with Strangereal. Personally I believe Infinity's plot and setting was created to continue this strategy but also as a throwback to the old games to keep veterans of the series happy and interested.