that's very fascinating, as someone who has only experienced Tokyo, I was amazed with how clean it was compared to other Eastern Asian cities (I lived in Shanghai). Wouldn't have guessed it was a bit of smoke and mirrors.
Compared to most major global cities it's night and day.
I'd take a hard look on NY, Chicago, L.A, London, Paris, Amsterdam, before I complain like the grandparent about the Japanese situation which is an order of magnitude better...
Tokyo of course is on a league of its own, but here's Osaka Street View, go around, how does it compare to what you read?
https://www.google.com/maps/@34.675107,135.5261238,3a,75y,27...
https://www.google.com/maps/@35.6960715,139.7029924,3a,75y,2...
We can compare that to a random spot in skid row, LA.
https://www.google.com/maps/@34.0413292,-118.2437281,3a,75y,...
https://www.google.com/maps/@34.6687543,135.5013888,2a,75y,3...
(Now let's compare with the sorry state a lot of European cities are in)
At night time I did see quite a bit of beer cans/bottles around, however, either people or cleanup crews seemed to group them together to make cleanup easier.
If this is due to cleanup operations, I feel other cities around the world should consider such logistics because it makes travel there one of the most pleasant experiences I've had.