Did you not notice that I specified “developed-country Gen Z above” and also China? That was to leave a carve-out for the still very vibrant everyday multilingualism of the Indian Subcontinent, sub-Saharan Africa, etc. But for East Asia, Europe and most of Latin America, the trends speak for themselves. I am not monolingual, nor are many educated people of my generation, but younger people in my country are likely to learn only English alongside their native language (and then stop being curious).