Twice supposed popularity internationally is so overestimated that it always sounds fake. Thinking that Onces are calling them the biggest gg in the US just because they were the "first" to hold a concert in Sofi Stadium would make them the biggest. Where did those attendance numbers went to?
Twice will always have sales thanks to fandom and inflation. But realistically speaking, they are already past their prime. Their leaving behind SK and moving towards the West was always not a good idea because they didn't even move past that. Yes, they did have the tour numbers and sales. But those sales and tour numbers do not match their streams which is the most dominant factor for popularity and relevancy right now.
Also, they are targeting the US market and yet they are still struggling.