Iran might certify it.
Russia might certify it unless having a viable domestic alternative. Moreover, it could reuse parts for its own planes.
These three taken together are already a significant chunk of the global market, each having a large domestic demand.
The problem with Tu-204 is that it wasn't a good market fit, like the current Chinese ARJ. It was certified OK and could fly abroad all right.
People said the same about Chinese cars and they're the largest exporter in 2023.
What if they have not one but ten generic passenger plane brands by 2040?
