The big innovation of 7/11 Japan that launched the convenience store craze in Japan was keeping as much stock as possible in lots of retail outlets and ready at point of sale instead of in warehouses.
for what it's worth I think a lot of the convenience store craze in Japan also comes from Japanese cities being very dense and heavily walked. Most of the states lives in a sparsely built suburban environment, using cars for most or all transportation, making it very easy and often preferable to hit up the nearest big box.
In Japan you're almost guaranteed a konbini between you and your destination, and this makes it easy and pleasant to dip in for a snack, breakfast while walking to the train, etc. This is only economically feasible in a dense environment with a LOT of nearby shoppers, particularly considering land costs in Tokyo.
(I saw a good article at some point how a lot of small-town and rural convenience stores in japan aren't economically feasible and they struggle to keep the lights on as corporate demands unreasonable amenities like being open 24/7)
In Japan you're almost guaranteed a konbini between you and your destination, and this makes it easy and pleasant to dip in for a snack, breakfast while walking to the train, etc. This is only economically feasible in a dense environment with a LOT of nearby shoppers, particularly considering land costs in Tokyo.
(I saw a good article at some point how a lot of small-town and rural convenience stores in japan aren't economically feasible and they struggle to keep the lights on as corporate demands unreasonable amenities like being open 24/7)