Humans are social beings and need to feel the closeness to other human beings. This does not mean, that Lisa Simpson is lonely - of course the exact level of closeness you need differs from human being to human being and she has parents after all. But more statistically speaking I would say that being alone does make you lonely, even though the reading German philosophers as a child part appeals to the exceptionalism of the other commenters.
But physical proximity is not emotional closeness. Being surrounded by people having negative effects (disrespect, incompatible value system,...) on you is far worth than bubbling alone walking in a forest.
Physical proximity certainly does help, that is why lovers cuddle and parents hug their children. They need this physical proximity to gain the ability to trust and build more complex relationships on more abstract forms of closeness.
I do not think that high intelligence removes this need and magically gives you the ability to create relationships or fight loneliness by brain power.
These are affectionate relationships and an exception rather than the norm. It's a massively important need, but you only have a handful of people you cuddle with. The vast majority of your relationship are social, smalltalkish, gossipish, etc.
