I would surmise that we can solve the loneliness problem without going back to having larger families which would only place more stress on the environment hastening our eventual extinction. The crux of the matter is having opportunities for meaningful social interactions daily. While this may have been provided by family in the past, there is no reason this has to be so as far as I can tell. If we can't solve the problem I would still rather have people able to choose their own paths in the world rather than have some arbitrary and oppressive system imposed upon them.