IDK man - this is sort of true, but I think you under-estimate how quality and price scale. A Jumbo-Choco-Monaka at 7/11 is still a fantastic value at ¥160 even if you adjust for purchasing power. GDP Per Capita (PPP) is about $85K in the US and about $60K in Japan, but even granting a 2x increase for California then a $2 choco-monaka would be a steal. As it is, I just spent $4.50 for an Its-It about an hour ago and while I am quite a dedicated fan of these things I would have gladly forked over ¥700 for a Chocomonaka if such things existed in California. I realize that people don't live out of 7/11 for their daily groceries and your point has some validity, but the quality/cost is still a great deal relative to what you would get in America.

It's pricier than a supermarket, but still decently good value even in Japanese terms.

It's not the exchange rate. It's 30 years of economic destruction and currency devaluation as the end result of horrific spending policies. If Japan doesn't right the ship, they'll sink into middle income territory over the next 30 years. Poland and Greece are now just slightly below them in GDP per capita - and Lithuania is above them (unthinkable circa the mid 1990s).

Realistically Japan is very close to being a second tier economy. It's quite plausible that Croatia and Latvia will pass them on GDP per capita over the next decade. 7-11 Japan would be relatively inexpensive for the citizens of any affluent nation, because Japan is so much poorer than it used to be.

And how had the Japanese inflation / cost of living changed over the last 10 years or so? I went there in 2015 and now hearing this I'm strongly thinking about paying another trip there... I mean, back then 1 EUR bought 135 yen and now it's 185, and I already remember restaurants to be pretty cheap for the average quality, while hotels/apartments sucked a bit - especially in room size.