You really have to like yourself and your own company to be comfortable about sole living I think. It also depends on the type of person you are, whether you rely on or crave company, or don't.
Take me for example. I'm late sixties now and have lived on my own since I was late twenties. I bought my own house when it was not easy for a single woman and I thought I had won the lottery. I am still in that house now because that first purchase was perfect for me, and still is, although it's much "grander" by now!
I'm not a recluse but I'm not a "joiner" of things either. I'd say I have built a life for myself that doesn't require much from others. I have family and friends that I can call upon at a minute's notice to help out in emergencies or whatever. My sister and I go away a lot also, although she has a family and grandkids I don't. Friends peel off as you get older, or they get sick and die, but I have a few constants around still for cultural things, coffee, walks and so on. I've known them since university days.
I also have a partner for over 30 years now. He lives in the country an hour away, and I'm in the city. It's a perfect combination for us. We share the attributes of each others lives, go out places during the week, and have mutually agreed trips abroad/away. But we would never live together in the same house. We both like our lives just the way they are!
So really, it's horses for courses isn't it?