maybe not necessarily an active social circle, but i think some form of human interaction is an important part of mental development and general maintenance of mental health if that makes sense. i think its important to have people/a person you can talk to, but remembering that some heavier topics are best talked about with a health professional, as many people arent prepared or educated on the best way to respond or help. i think social interaction is especially important for kids as they develop their identity and learn important social skills they'll need in the future etc.
obviously nothing can be applied to every single person, some may not desire human interaction and may prefer interacting with for example animals or ai, which is perfectly reasonable. i myself much prefer interacting with animals and avoid human interaction as much as i can just bc of how stressful i find it. ive always been this way for as long as i can remember, but i know certain situations in my life have caused me to be more averse to humans if that makes sense. being autistic with social anxiety makes having a social circle difficult, but im ok with that bc i dont feel i need a lot of friends, just a couple close ones. for a period of my life as a teenager i didnt want any friends at all and cut ties with everyone i knew bc thats what i believed was best for me at the time.
i think everyones different and has their own capacity and requirements for amount of as well as type of social interaction, but overall humans are naturally a social species, we evolved in groups (like monkeys and elephants and ants etc., as opposed to solitary animals like tigers, polar bears and some species of birds etc.), but its no good forcing yourself to have an active social circle if its not something you personally need. hope this made sense. its a very interesting question! id love to hear any thoughts or disagreements you have with anything i wrote.