I'd like to see some statistics for that. IIRC most of the big marvel/dc comic movies did significantly better in the US than outside. It sort of makes sense as well, those comic books were not as big for the generation that is 30+ now in those other countries.

The too complex dialogue argument also doesn't really make sense considering that movies get translated in the biggest overseas markets.

Stats:

https://www.boxofficepro.com/box-office-rewind-a-history-of-...

Marvel films make most of their money internationally, the bigger the film, the bigger the foreign share. E.g. Infinity War $357.1 million domestically and $1.2 billion worldwide.

> The too complex dialogue argument also doesn't really make sense considering that movies get translated in the biggest overseas markets.

The argument is that it's much easier to get plot, jokes, and moderate character development across in translation (and more convincing to dub!) with a base script that uses simpler English.

Comic books have little to do with it. Guardians of the Galaxy never sold many books, and only to pretty hardcore fans.