Language doesn't matter, having something to offer the world is what leaders want from everyone. Being smart is beyond learning a certain language. President Macron was in the US and had to address the press in French. Trump said that's the best language in the world, and in my interpretation it's because of the service France has to offer the world. In recent times we must focus on solving problems than learning languages that isn't ours. Interpreters are always available to translate, hence, I wouldn't consider English a supreme language to climp the ladder of success, because some of the people that's invited in the oval office, are not English speakers.
The beauty of technology is that one doesn't need human interpreters anymore to understand a strange language. All you need to do is to install a language interpreting software. There are so many courses or jobs that technology is making obsolete, and one of them is linguistics study. It was very popular few years ago to learn one of the foreign language but it seems less people are chosing such course these days. Learning a second language should be made optional in most schools. Students should be taught in the local language instead of being forced to learn a strange language.