Alright, hold those horses.
A few points I'd like to make regarding your assumptions and my view of Japan, which I'm not claiming is fully correct, but has a different perspective to offer:
a) I'm not an expert, but Japan's debt is mostly domestically owned (companies in Japan, Bank of Japan, et cetera) and they hold huge reserves in foreign currencies. Economics is more complicated than a simple debt figure, and I'm not well informed about the details, but the ratio of "debt to GDP" by itself isn't the holy grail as far as I know. Devil's in the details. It's a huge problem, but not as large as the number by itself indicates.
b) Japan is self contained. They have a unique self contained non-extremely-western-poisoned culture, an aging population without relying on immigration, their ethnicity makeup is 98% Japanese (I'm sure them being an island, the language and culture barrier are a factor). Find that bad or good, but I think there's something to that, and I think it's important when discussing their culture or their country.
c) Japan is a paradise for geeks, regarding how many possessions are treated and treasured. You've seen outdated tech and thought it was bad? I'm here ordering old consoles, games, dvds, books from Japan and the condition "slightly worn" from a Japenese seller is the American equivalent to "As good as new, perfect condition". Japan is a paradise for cameras, old game consoles, hard to find hardware, watches, ... arcades you wouldn't be able to find in any other country because they've given way to "the times" in other countries... you see a fax machine, or I guess potentially minidisc player, a discman, old cassette player... sold as "new" and think it's bad? I'd love the fact and buy all of them...
d) Toyota is one of the top 10 companies by revenue in the world, still one of the largest car manufacturers, and famous (among other Japanese companies) for efficient and world pioneering management techniques... Japan has the third highest GDP and ranks 19th in the HDI... is it maybe too soon to sing their demise?
Not picking a fight, but from my perspective your comment comes off as condescending, culturally biased and close-minded... Deriding a whole country/culture/economy because of how you interpreted certain things while visiting...you're citing Japanese toilet buttons as an example for their technological demise given their bad UI (having buttons)? Should it be voice controlled, have a touch panel, connect via Bluetooth to your smartphone and have its own bespoke App, offer fancy usage statistics...
You were there for months and this is your cynical take? How could I, as an outsider applying a similar spirit to yours, rate China (censorship, the CCP, inequality, corruption, certain infrastructure projects, technological tracking), the US (politics, cultural crazes, depression, high school system, prison system, weapons, policing), Europe (immigration and identity crisis, EU, ...), Russia/Ukraine..., Mexico, Brazil,...
This is meant to illustrate: a cynical take is easy to come by...