I’ll add in Tokyo Xtreme Racer to your list. While it’s limited to Tokyo’s expressways, it does those very very well. And it features some delightful japanese jank too. Top notch game.
Also worth mentioning are the touge battles in the original GRID. Though, dissapointingly, I couldn’t find this one for sale anywhere - you might have to source it on the seven seas.
Honestly the biggest reason might be the population density and structure in Japan. People live and travel between large metropolises, and those are relatively close, so this makes train travel more cost-effective.
Otherwise, this “only” makes the shinkansen great. Because regional and local trains are pretty much the same as any developed country ( albeit very very punctual ). Great train networks aren’t limited to Japan. European trains fare the same except some lack of punctuality, and the lack of central backbone, due to the amount of international borders. Chinese high speed rail is actually better quality-wise and more connected than in Japan, but local trains are meh and extremely crowded. Honestly it feels like the US is the outlier here, because they had decent rail and managed to fuck it up in favour of road traffic.