There will be a time in the future for sure that he will have to fight in other countries like in US or somewhere in Europe, or even in the Middle East if Inoue will face an opponent that have a much bigger name than him. But not now because the organizer and promoter is more inclined to make the fight happen in Japan as it was already evident that they can generate big profits in that certain country and considering that Inoue won this fight and will take the undisputed fight, I'm also confident that they will contest the fight in Japan again instead of the Philippines where Marlon Tapales came from.
Actually, even if Inoue will face a much more popular or so-called
"big name" opponent compare to him, it's not the basis of where the fight will take place. Since boxing is associated with business, big matches should only take place at proven associated with a big market.
If let's say Marlon Tapales will have a shot at a unification fight against Naoya Inoue, just in case the Japanese monster won this match against Fulton, don't expect that the Philippines might be chosen as one of the venues even for consideration.
And besides, I see that it's boxers are even more determined for the guest to pulverise the host.