Well, if you don't think it will be terrible for you, consider that there are a lot of other people out there for whom it won't be terrible for either. I mean try to focus more on how it's not going to be that bad for others.

I don't know about the children part. There are many, many people in nursing homes with adult children who rarely or never visit. Or elderly who live alone, who have home health aides or in Assisted living facilities since their children live in another state. I don't think having children is a guarantee that people will have a motive to want to continue living in their 80s. I do agree many who are ill or disabled AND alone or with very little social support, will most likely not have much desire in living or be happy.
I think the key is having social support, even if it's not relatives. There are some assisted living places - Very different than nursing homes- where the elderly have their own apartments, have activities in the place, go on trips, have friends, etc. and can live happy in their old age, since they are surrounded by people who share interests or have activities to keep them happy to be alive and derive some type of joy out of life..in spite of having some health problems (most will have some or many in their 80s).