You cannot have a real major powerful country if the people can't communicate with each other. You cannot have a people.
All of these countries with multiple languages on the list are tiny, monolingual in practice or struggling with separatism/conflict. Most fit into into at least 2 of these 3 categories. And certainly none of them have 20+ official languages.
https://www.nationsonline.org/oneworld/european_languages.ht...