they are capitalizing on those things that make us happy now... E.g Data
it is indeed logical to stay alone and save money but old age will tell on such a person, when it becomes difficult to move around and if unfortunately, such a person didn't earn enough to save him in old age, it becomes a big problem, we need companionship and our blood, so they can take care of us in our old age.
Sadly, in this world we are now, a mother can take care of 4 children but 4 children can't take care of their mum because they are still struggling to make ends meet.