I think there are also issues of scale of investment and revenue splits - I can't find right now, but there was a rant tweet from a Japanese comic author that apparent typical compensation for webtoons was below labor cost of his team by couple digits, and I also remember seeing similar rants on topic of AI training materials that were off by even larger magnitudes(like $.25 per dozen images one-time vs $1k per use recurring).

So authors seem to be getting paid more, and that leads to an obvious question of how. One possible answer to that is maybe Japanese media contents - be it images or anime or light novel or classical novel - are still heavily subsidized by its strong and isolate domestic consumption. Average household expenditure on reading is about $120 per year in US and $325 in Japan[1], which IMO roughly coincide with this hypothesis.

If there actually is such a situation... maybe what's missing in Western media is just accelerated consumption. It's weird to think that Americans and Europeans might not be consuming enough media, but that could be it.

1: at current rate of 150 yen/dollar; raw value is 50k yen or ~1% average yearly income