I'm not sure about "more demand", but I wouldn't be surprised if multi-language ability were to seen as more distinguishing in a world in which language translation is readily available - i.e. "can do what most rely on a machine for". I don't think "why do they trouble themselves instead of just using machine translation" would happen any time soon, since being able to speak a language yourself still affords the most direct communication path (unless it falls out of fashion to talk face to face).
Especially since this is something where it's not possible for machines to truly just eclipse humans -- if you're fluent, you're fluent. Of course machine translation easily surpasses human speakers on vocab, but you're more or less bounded by what the recipient/listener can understand, anyway.
But demand for translation services will likely dwindle.
That said, one of the best reasons to learn languages is simply the mental exercise, and unless we change the way humans learn and maintain mental performance, that will remain true.
Especially since this is something where it's not possible for machines to truly just eclipse humans -- if you're fluent, you're fluent. Of course machine translation easily surpasses human speakers on vocab, but you're more or less bounded by what the recipient/listener can understand, anyway.
But demand for translation services will likely dwindle.
That said, one of the best reasons to learn languages is simply the mental exercise, and unless we change the way humans learn and maintain mental performance, that will remain true.