I thought you said its not going to be a lengthy post😂😂, well , i will not make my comment lenghty too, anyway let me see if i can keep to my word.

Firstly, we humans are built to be social creatures, so when our brain starts noticing lack of social activities, it begins to secrete the pleasure hormone(dopamine) to make us try to reconnect with people and feel happy.

Like it has been said that human are social creatures,when we refused to socialize,our brain takes over to enforce us to do so by secreting dopamine which is not good enough.

The word of God said somewhere that "God set the solitary in family,but the rebellious will dwell in a dry land". Man was never created to live alone. Self isolation spell doom and should be discouraged. Family members should help anyone lonely. Like you said, old people are the most vulnerable to social isolation due to the fact that children have grown up and left home. Your post has provided solution which is being involved in social group.
Also,parents these days tends to stay glue to there laptop trying to finish one work or the other, well they need it to keep on putting food on the table for kids. During this time of lockdown my kids eat more than usual. 😂😂😂.
This is a good write up,thanks for sharing @menoski