You mostly adapt your fridge size to your way of living. Living off of sales, not having a decent convenience store nearby, making meals preemptively etc. all contribute to having a bigger fridge. This was still pretty bad here a few years ago when most shops in a 30km radius would be closed for multiple days on end for religious holidays, most big families would stock up big time.

That's the big thing Tokyo does best. If going to a convenience store is actually convenient, you don't need a large fridge at all, except for some niche situations most people don't care for anyway (cooking dishes which require a lot of space in the fridge/oven/freezer). I'd also wager eating staples kept in cupboards helps.

Can't speak for the remainder of the kitchen though. You don't need 4/8 stoves, an oven etc., but appliances don't take that much space when packed together. Even fridges don't really take that much more space.