I do not think you have to learn a foreign language to live or work well at your native country but it seems to be a trend that more people would like to learn foreign languages to get access to other countries' culture. Not only economic reason drives the trending, but cultural globalization is also pushing the trending and coax people to learn a foreign language. 

I would say for many reasons like personal interest, a future trip or a job. 

Hi! I'd be more willing to help you :) Just send me a message :)

Well not everyone can speak English, lots can but not everyone so I find it useful to at least learn one or even two other languages along with English, I learned how to speak English and Spanish two very widely spoken languages and now I learn Russian another spoken language quite largely at least in East Europe. So yes you should learn English but learning another foreign language or even two is even better for some can't speak English.