It's Nestle in the UK, and they don't sell the Japanese bonus snacks here either.

It's also hard to understand just how popular KitKats are in Japan and how their products and limited time offers cater uniquely to the Japanese audience.

KitKat has a lot of competition in the UK where caramels are way more popular than weird KK flavors.

License it to Mondelez and suddenly it will have lots of flavors you won't likely buy....

KitKat are already full of wafer so Mondelez wouldn't be motivated to 'put anything in the chocolate bar at all so long as it's not chocolate'. What's cheaper than wafer? I guess if they can make more of the inside wafer, so there's less chocolate coating?

Perhaps you can make wafer bubbly, so it's more air? Although it's cheaper to just put it in a plastic wrapper and fill the wrapper with nitrogen...

If you go to the Japan Centre in London you can find various flavours of Japanese Kitkats.

I can't recommend anyone going to Japan Centre because you will spend a lot of money.

Last time I was there I spent about £100 on sweets that had tiny little train cars in them and the chocolate was terrible and I ate all of it.