I saw a few comments here commenting this. It's a strange perspective to me. The people I know who are bilingual still prefer one language and use the other primarily to speak to people who don't know their primary language.
As an example I am Swedish but fluent in English and Dutch. In my family we use a mix of Swedish and Dutch. But I use Swedish exclusively with anyone else who is Swedish unless someone is in the conversation who only knows English. I have both friends and colleagues who don't speak Swedish (nor Dutch) and I always speak Dutch with my wife's family.
In this context it makes little sense that I'd simply stop using multiple languages, since then I'd be unable to speak to parts of my family, friends, and coworkers.
As an example I am Swedish but fluent in English and Dutch. In my family we use a mix of Swedish and Dutch. But I use Swedish exclusively with anyone else who is Swedish unless someone is in the conversation who only knows English. I have both friends and colleagues who don't speak Swedish (nor Dutch) and I always speak Dutch with my wife's family.
In this context it makes little sense that I'd simply stop using multiple languages, since then I'd be unable to speak to parts of my family, friends, and coworkers.