I think it's fair to say that even in a post-Breath of the Wild world, for almost all intents and purposes, most people, developers and players alike, probably consider open world games to be mostly the dominion of western developers. Although the very earliest roots of Japanese experimentation in the genre actually date back to a similar time frame as western efforts by way of games such as Doukyuusei for the PC-98, it wasn't without a kernel of truth, at least depending on whether and how you qualify a game's environments as open world.. If we're talking about vast sandbox-style games in the mold of Grand Theft Auto III and onwards specifically, then, yeah, budgetary realities previously meant few Japanese developers had the financial means and team sizes to seriously attempt them, let alone compete at an international level. It's not say that there weren't games that tried, especially around a decade, decade and a half ago, but it's fair to surmise that few left any lasting impression and some games outright crashed and burned for getting too close to the sun.
The problem with this mindset is that it presupposes that open world games are, by their nature, a format of action games first and foremost, if not exclusively. Games like GTA, Just Cause, and Saints Row where you have an antagonistic relationship with the environment and the fun and pleasure come from subjugating that environment and its denizens as you increasingly navigate and engage with it on your terms and only your terms. It's true that a lot of the most globally successful examples build upon such templates, and for perfectly understandable reasons. In a world of suffocating socioeconomic realities weighing the majority, for those in the poor and working class, there's a real catharsis to be felt in attaining a digital safe space to cast aside their inhibitions and be on top of the world for a change, and an often violent change at that. I felt as much in the summers I spent in New Mexico taking turns with my cousins seeing how long we could all survive in Vice City and it's a premise that's only gone on to resonate to exponentially higher degrees over time.
But it's not the only way to make open world games and the real reason most Japanese open world games don't look as though they can compete to that standard is because they aren't. The open world ideal as expressed through Japanese games tends not to be an action game, but an adventure one.
I meant to rechost this sooner since I know I originally posted it at an ungodly hour for most people, but here's an impromptu essay I wrote last week about Natsumon, the open world summer break 'em up from Boku no Natsuyasumi and Attack of the Friday Monsters creator Kaz Ayabe. It's about the design paradigms and genre inspirations that tend to inform the best Japanese open worlds and how they can still capture my attention time and again years after the western AAA take has worn out its welcome with me.
It's also secretly an essay about PachiPara and why a pachinko sim with an open world RPG side mode still lingers in my mind a decade later. It has been a genuine, years-long struggle to figure out where and how to even begin discussing that series' profound impact on my outlook on Japanese games. My coverage and arguably even parts of my career wouldn't be what they are without those games. But it turns out a humble little game about a kid just running and jumping all over the place in open fields was as good of an opportunity as any. 
