Are you trying to say that someone who is 40 is just supposed to not have a social life anymore?
“Aging population is becoming less social overall” is not a surprising statement.
The 55+ crowd where I'm from have the most active social life. Constantly at each others houses for a chat, activities (gossip parties) after Sunday mass etc.
Early to mid forties is middle aged in G20 countries, my own university days were 40 years past.