Shut themselves totally off? Or just no physical visits?
My mom had 10 brothers and sisters. A few spread out across the country and one to another country for a few years. Some we only saw at Christmas, some only every 4-5 years. I don't remember anyone complaining of any regrets.
A friend of the family, since as far back as I can remember, is an older woman with only 2 sisters left. They are all very active and healthy. They decided to have a private Thanksgiving breakfast. Unbeknownst to them, one had caught corona from her granddaughter. They all three got it. Two went to ICU with covid. One didn't make it. The one that caught it first survived. She is devasted with guilt. I'd think she would take regret from not getting to see them over that any day.