Spanish speakers in the U.S. are a dime a dozen so being bilengual here is simply not a competitive advantage. If financial gain is the only goal, you are much better served spending your energy on an advanced degree, MBA, etc. The only jobs that really require Spanish speaking are retail jobs in areas heavily populated by illegal immigrants. None of these types of jobs are relevant to this discussion.
The real advantges to learn other languages are to gain an appreciation for other cultures and countries, particularly if you learn as part of an immersion program or study abroad program.
However, the people who say that Americans will have to know Spanish to function in the future are full of BS. That is purely an urban myth.
