Hardly. I think it can arguably said that in the Western Hemisphere and certain parts of the Eastern Hemispher knowing English is in general more valuable than knowing any other single language.

That hardly makes it the only one that matters. I personally have derived enormous benefits from studying Latin. There have been several times I have wished I spoke Spanish and a few times I had wished I could speak Japanese, Pashtun, Arabic, and Dari.

Knowing more languages is definitely a good thing.

Try to get a job or start a business in mainland europe without knowing another eu language besides english.

Knowing multiple languages is extremely valuable.