There's some important organizational differences: Stores in Japan are almost entirely franchisee-operated, while stores in the US are more-or-less split 50% on being franchises or corpo.
It's hard to draw conclusions when they're shaped so differently.
But I can say this: Speedway is a large US chain of gas station/convenience stores, with ~2,800 locations (all of them corpo). They varied a lot; some had hot made-to-order food, some others were limited to roller dogs and baked, frozen pizza that was in many ways indistinguishable from cardboard.
There has never been a time when Speedway was awesome, but there have been times when it was acceptable. It was usually better in the suburbs, and worse in the cities (I've seen some weird shit happen at Speedway stores in cities, but they generally kept up with the chaos).
Overall, I'd give 5/10 -- it was often convenient and generally open 24/7, but at all times any of them could have used a lot of very obvious improvement.
5 years ago, 7/11 bought Speedway. They've subsequently managed to allow it to become even worse. Things are dirty, disorganized, clearly lacking any direction other than that which leads towards dilapidation, and the staff just doesn't appear to care about any of it.
Under 7/11's ownership, my buying habits have shifted from "Hey, there's a Speedway. Let's stop in and get a soda or some coffee, or maybe a sandwich" to "Oh look, it's a Speedway. Let's keep moving."
Their accomplishments here are very impressive.
Here in Ohio (the former(?) home of Speedway) things are looking up. We've got Casey's and Racetrac, each with generally-tidy stores and usually a decent selection of tasty, hot food. We've got Sheetz and Wawa expanding, with always-tidy stores and an outstanding selection of fast, made-to-order food. And as of April, we also have Buc-ee's: That place can be a destination in and of itself just for the brisket sandwiches and Beaver Nuggets, but the wall of hot sauce and the beef jerkey bar pull quite a lot of weight as well.
That leaves plenty of room at the bottom for the locally-owned bodega. These places are trash, there's usually no prepared food, and I do not wish to see the bathroom (ever), but they serve their neighborhoods' needs. It's easy to walk over there and buy whatever (I just got back from visiting the one down the road, in fact), and the bodega man is a genuinely-friendly dude who remembers his regular customers and is responsive to whatever they want him to stock. Despite the clear limitations, a good local bodega is a thing to be treasured.
But I don't see 7/11 making moves in that direction -- at least here in the States. They're moving so far down-market that they're approaching the bodega space, but they're doing this by shedding all of the redeeming qualities they may have once had. They're both blind and unresponsive to customer needs, and they don't care. That's all bad.
The distribution network even shows up in maps. There will be clusters of 7/11 in Japanese cities which is more efficient than spreading them equally.
It wouldn't make much sense to develop infrastructure around a source of rapidly-expiring food before that source existed. But once the food is there, demand for it will quickly develop.
There's a general theme in policy discussions of people saying "system X has a feature that system Y does not have; therefore, moving from system Y to system X must require a fully-developed auxiliary system to be in place for dealing with that feature before the move can even be considered a possibility". This is complete nonsense; it's what people say when they want to object to something, but don't have any reasons.
It's the kind of problem can often very nearly resolve itself.
Here in the States, I've seen what can happen at the end of the night at a busy Little Ceasers in a not-great part of town. They've got a lot of unsold pizzas, already boxed, that they simply need to get rid of so they can close up and go home.
So they walk out the back door with armloads of pizzas and... casually give them away to the people who are waiting out there. It's a very calm and surprisingly tidy process that goes by quickly. This happens at the same time every night.
The only apparent cost is whatever it takes to maintain the base amount of humility required to let this happen instead of dutifully marching the pizzas over to the dumpster and tossing them in.
This routine is almost certainly an invention of evolution, instead of planning.
Giving expired food to homeless people is not really a thing there either.
What new impediment does the geography bring to the table?
In terms of geography though, Japan has an extremely efficient and well developed cold chain and the country is pretty much a line from north to south. The US is clearly more spread out and significantly larger than Japan. That causes problems with both delivering the food to stores and (as other people have mentioned) efficiently moving waste to food banks.
Is that sector ripe for consolidation?
coincidence?