I think that pets are just more important to some people than they are to others. Many people, regardless of how their health is, have no use for a pet. I have a good friend who is that way. She is my age, and has the usual ailments that seem ot come along with aging; but she would not want any kind of a pet to take care of, and even when we were younger, she was never really interested in any kinds of animals. I don't remember her even having any kinds of pets for her kids when they were growing up, either.
I am just the opposite, and whether I have a busy life, or am a stay at home person; I just like having animals around. For me, it also helps me to stay healthy. Going out and walking a little with my dog is good exercise, and even just knowing that he is sleeping next to me when I am sitting on the couch makes me happier.