It’s a demographic issue. They (Japanase diaper producers) started making more money on adult diapers last year or so because of the change in demographics.
The market for diapers is unusual local. Partly because every country has local producers and partly due to local customs, tradition, legislation, standards and cost of living. It varies a lot by country and once you’ve found one brand that works, then you’re set for the duration of when you need them.
For babies that’s two years or so. No blame for anyone having to use them longer or whatever, but from a business point of view, it’s a two year customer relationship. This short period is very influenced by getting informed by other parents, because there simply isn’t time to try out every possible brand. Time is one thing, but also not wanting to change from what works, and just not taking chances.
Adult diapers are different in that regard. It might still be local quality pricing and trustworthyness, but the duration of the customer relationship is 10-20 years or more. The customer base is smaller but they’ll use them for longer.
It would theoretically be a good business to make a good quality diaper for adults and ship them worldwide at a good price, but it’ll be difficult to breach the market as a newcomer, because consumers aren’t really going to take chances on this issue, so they’ll rather buy a locally renowned brand.
Japan is (one of the) first countries to break this point. It is also happening elsewhere, but it’s difficult to know for sure, because it is only visible in the figures from local manufacturers who make both products, or by comparing wildly different segments using different products.
Anyway… I just find it interesting from a business and demographic perspective, because the product used to avoid shitting your pants is different from other kind of products in that regard.