I think them doing Japan next is likely but the tweet specifically says "in honour of our impending arrival on PS5" so I think it's just PS5 = Japan sales related.
My doubt I guess is more just that it’s so obvious of a choice combined with two other factors.
Japan is definitely held sacred to many both domestic and foreign so the amount of pressure to make it great is gonna be higher then a lot of other choices.
Also the fact that got some reason they chose Mexico of all places and I don’t mean any offense to any Mexican members or Mexico in general but I’ve been in the car scene since I got my license at 16 and deeply interested in it since I was like 7 in the late 90s(GT combined with TFAF really just catapulted me into a lifelong obsession with cars) and I’ve never really heard about Mexico being a hotbed of car culture. Obviously SoCal had a huge culture but I’ve never really heard any specifically about Mexico and yet they chose to set 5 in Mexico which I don’t really think gave any specific flavor in cars or scenery like they had with 2/3/4.
That being said I also thought Colorado was an odd choice with the original.
Europe made sense with great scenery and clear and obvious car history, Australia made sense with varied terrain/scenery and unique car culture as Australia has always had access to JDM classics and a deep history of unique home brands, and the UK brought a lot of fresh scenery combined with rich car culture both domestic and foreign.
Colorado just seemed like an odd choice for a US state, and Mexico was basically Australia 2.0 but without a clear and well known car culture.
Again no offense to Mexico at all, and if anything I’m sorry they got such a mediocre Horizon game.
Also Assassins Creed is a good example of my first point as Japan seemed like an obvious choice but they didn’t do it right and that game is all but guaranteed to bomb whether critically, financially, or just general customer sentiment.